Despite not having had any problems in the past, I certainly won't be flying with BMIBaby again if I can help it. Having paid extra for snowboard carriage (£18) I still got stung for £60 excess baggage [East Midlands to Geneva last week] as my combined baggage weight was [according to their scales] 5.3kg over the current allowance of 18kg per bag. They are now strictly enforcing the £10 per kilo excess baggage rule which means a 31kg bike bag would cost you £130 ONE way in adition to the additional baggage cost of £18 for the bike
My snowboard bag contained only board, boots, bindings, shovel & probe and it still weighed 20kg according to them – I doubt I could pack a mountain bike so that it only weighed 18kg and paying the excess baggage can make the total cost more than a flight to Canada!