an unfair allocation is indeed often becoming a problem on the bounty. The manager should at least give you an idea clearly to indicate the allocation they provide so that is not the case a misunderstanding. but only a small part of the bounty and a bold manager want to give information when discrepancies occur.
The problem is when they are all not even reading the rules and agreement properly before try to join in any bounty. If they are realizing the agreement that has been putting by the team and they should put their main concern on this word " the team can change the total allocation anytime" To create any protests will be worthless.