It"s certainly not ideal when a lot of hotels, like the one I"m at, have a checking in time of 3pm.
When it was booked an hour and a half was plenty of leeway to get there in time for the start - and wasn"t the reason to have the early registration so that people could make their plans?
Was there much point in letting people have so much time - then changing the details at the last minute?
Doesn"t bother me at all personally - in fact, I"d prefer the early start.
BUT, that"s not important. Jon has a very valid point, and people who are travelling from a distance and have planned their travel arrangements to tie-in with the start time might be penalised by any change. However, the start isn"t changing that radically, and people should already have included some slippage into their plans in case they are held up with their flights/car journeys, etc. Of course, if you arrive late, you aren"t penalised other than being blinded away slowly.
It"s not ideal - and it"s a shame the earlier start wasn"t sorted and announced earlier.