When a team enters the lion's den that is Clermont Auvergne's Stade Marcel Michelin, they encounter not just a squad of 23 players but an entire movement.
Defeat for the home side is a personal affront, such that it has not been achieved since Biarritz snaffled a last-minute try to win 16-13 on November 21, 2009.
To last 50 games without one's fortress being sacked, in such a competitive environment as Top 14 and Heineken Cup, is a remarkable feat of endurance.
Backed by the rabid, raucous hordes of yellow-clad support, whose constant chanting is embellished by a cacophonous concert thanks to the repeated pounding of thousands of sausage-shaped balloons, Clermont and its support are inextricably linked.
Given the remarkable efforts of Leinster's visiting multitudes last season for the pulsating semi-final victory – in nominally neutral Bordeaux – the majority of the 18,000 home faithful will surely redouble their decibel levels this time.
Given the close proximity of supporters to the pitch, it all adds up to truly one of the most intimidating citadels in the game. "It just sums up what's facing us really," remarks Gibbes. "In the quality they've got, the depth they've got. And the support they have is bloody intimidating for players and for the officials as well, I'd imagine."
Leinster head coach Joe Schmidt is on record about how influential the crowd can become – of course, he has experienced both sides of the equation, forming an influential part of the coaching team under fellow Kiwi Vern Cotter that instigated the proud record.
Last season, Wayne Barnes refereed the sides in France for a second successive time and was relentlessly targeted by the home crowd; albeit Leinster won the penalty count 13-12, despite a late flurry of awards against them.
All this – the home support, the influencing of referees – is before you even contemplate the team itself, compiled on the back of a Michelin-sponsored budget of some €25.2m which, even if only slightly modified in the off season, boasts a formidably mouth-watering roster.
While Leinster seek to cope with the absences of their global stars Rob Kearney and Brian O'Driscoll, Clermont could afford to pitch up in Toulouse last week and bench Benson Stanley, Brock James, Elvis Vermeulen, Ben Kayser and Vincent Debaty.
Oh, and if that isn't making you drool, consider the fact that a stellar half-dozen watched proceedings from their couch – namely Wesley Fofana, Thomas Domingo, Napolioni Nalaga, Julien Bonnaire, Lee Byrne and Sitiveni Sivivatu.
That the James-inspired onslaught towards the end of last Saturday's 30-22 defeat to Toulouse almost conspired to extricate an unlikely bonus point represents a remarkable testament to the strength of their squad.
Only the long-term injured flanker Gerhard Vosloo and powerful wing Julien Malzieu – Shane Horgan's torturer when he scored a hat-trick in the 2010 RDS quarter-final that Leinster squeaked 29-28 – will be absent when Cotter names his line-up tomorrow.
Just as one recoils with trepidation on assessing a backline teeming with powerful, skilful footballers – Aurelien Rougerie, Fofana et al – then you have to address the inestimable influence of the little master, Morgan Parra, pulling the strings at half-back inside the mercurial James.
If that doesn't scare you, then what about the pugnacious pack performers, from the irascible Jamie Cudmore to the irrepressible Nathan Hines, buttressed by the hard-hitting tackle machine that is Bonnaire.
Only a foolish coach would perceive their regular, forward-oriented bashing in the Top 14 to typify them; far better to rely on the evidence compiled in both bonus-point victories en route to their pre-eminent position in this Heineken Cup pool.
"I'm not sure I'd buy into that," agrees Gibbes. "There's no doubt they've got some serious firepower in their backs – Sivivatu and Nalaga, you'd still see them as massive weapons.
"But they've got some good resources up front. The Top 14 is a bit of an arm wrestle and so maybe the perception is based on just a little bit of Top 14, which is like that.
"I think if you saw the Exeter and the Scarlets performances, the shifting of the ball did come in from deep and from behind. The wall was pretty impressive and backs and forwards linked in there, doing a lot of damage.
"Collision-winning obviously is a challenge, they've got bigger guys physically. The size of the challenge is (in) their pride and their home record, perhaps based on how their campaign finished last year (perennial challengers, Clermont have only one national title to show for their millions of investment).
"There's their familiarity with us, including last year. And then you've the field conditions. It can get quite heavy, that field and you can get into some real trench warfare."
Leinster must be prepared for war.
"We've played them three times in the last two Heineken Cups and here we go again," puffs hooker Richardt Strauss, acknowledging the difficulty of facing down 'Les Jaunards' once, never mind the return on Saturday week.
"These games are going to be so tough. Anybody who's watched games between us in the past knows these matches are unbelievably close and incredibly hard.
"We're going to have to go to some dark places to get anything from them.
"Those games against Clermont were some of the toughest games I've ever played in my life. They kept coming at you all the time. They are big, massive men and having knocked them out last season they'll be coming for us."
Leinster are forewarned and forearmed. But frightened? Hardly. After all, they are the two-time champions, defending their own proud unbeaten record of 17 games in Heineken Cup combat.
"We can't afford not to get four points," stresses Schmidt.
As Ol' Blue Eyes once crooned, when the irresistible force meets the immovable object, something's got to give.