Older son played BA for years and the whole thing is pretty funny. Let me tell you, more than winning tournaments it was about filling-out line-ups which were often thin due to vacation (holiday weekend), illness (flu is going around), poor communication / team management (known for that) and things like this. So A) it's about filling-out rosters in need.
Next, my experience has been sometimes it's a matter of letting kids try different teams and different levels of play to see if the can handle it or if the they have improved to move up - you know, a gauge to their development and helping them move along. So B) it's for the player.
The last thing in my experience has been the organization being hell bent on winning a 10 year old's fairly meaningless hockey tournament. We have been part of other organizations who have verbalized to the kids and families that the only goal for tournaments is to make it to the finals and everyone was expected to do everything to get there. BA never mentioned tournament results or expectations.
These have been my experiences and I still find it hard to believe people think that an organization who is placing kids on top Jr. teams and moving kids on to D-1 and D-3 college teams and working with NHL players is worried about a 10 year olds tournament enough to cheat.