Yes it would. Kids when they are that young tend to let things distract them to the point that they ignore the fact they need a wee. My 5 year old is always getting carried away when hes playing and will all of a sudden realize he needs to go. If you stopped him going and he ended up wetting himself in front of his class mates I would take that up with your headmaster and the board of governors.
When my 12 year old was going through the Primary system he was the same. If you think the kids are taking the micky and just doing it for a cheeky skive then you can normally suss this out after a couple of weeks but you risk a difficult chat with a parent if your wrong.