We've had our fill of football yobs harping on about the off-side rule, which anyone dull enough to care knows is open to interpretation.
According to the sport's governing body, Fifa: "A player is in an offside position if he is nearer to his opponents' goal line than both the ball and the second-last opponent."
Whether, though, the player is committing an offence is a matter of opinion by the lineswoman (or, for that matter, linesman). The grey area concerns whether the player is "interfering with play or interfering with an opponent or gaining an advantage by being in that position".
In contrast, the Europe-wide rules on passenger care when a flight is cancelled, for any reason at all, have no room for dispute. Period.
Passengers must be found some alternative way to reach their destination, for example on the next available flight or from the nearest airport.
In the interim, "passengers shall be offered free-of-charge meals and refreshments in a reasonable relation to the waiting time; (and) hotel accommodation in cases where a stay of one or more nights becomes necessary". No ifs, no buts, nor any pleas of "extraordinary circumstances" allowed.
In December, Roger Randle turned up at Palma airport for a flight to East Midlands in Britain. But Spanish air-traffic controllers didn't turn up for work that evening. At least Mr Randle had the reassurance that he would receive board and lodging until the next Bmibaby flight to East Midlands, three days later.
There are many worse places to be stuck than Mallorca's gracious capital, whose lofty cathedral towers above a genial confusion of Moorish ruins and Spanish flourishes. Once the stranded traveller has left behind the less-than-genial confusion at the island's airport, she or he could take advantage of an extra few days in this lovely city or bolt on a dramatic rail trip over the mountains to the town of Sóller.
But, as is often the case with sudden, mass cancellations, the letter of the law was at odds with what actually happened. Bmibaby's ground representatives told some passengers to find their own accommodation and file a claim for reasonable expenses.
Mr Randle flew home on the rearranged flight, and sent his receipts to the airline's headquarters. But no wizard worked wonders on his €700 claim; instead he was told that the airline was "unable" to settle his bill and "any claim of this nature should therefore be directed to your own travel insurers".
Mr Randle tried but, unsurprisingly, given the airline's liability, the insurer said "no". That was when he got in touch with a newspaper, who in turn contacted Bmibaby.
The airline changed tack in the manner of a nippy winger: "If Mr Randle has confirmation that his travel insurance company will not cover the additional costs, then Bmibaby will review the claim and make a reasonable contribution towards the costs in line with the EU regulations."
Is Mr Randle alone in being given this strange interpretation of the rules? Let me know at email@example.com.