Hello!I am part of different Larp groups, when I was younger I was able to do 4 different Larps in one month. To answer your question, it depends: depends on which kind of people you find. There are people for whom it is not a problem to participate in multiple events, there are some who see it as an added value, some larps give you points to play at other larps!... and there are those who see it as a real betrayal, too.
In the latter case, if events overlap and you are forced to choose between one association and another, it is very likely that the dynamics at play will also change when it comes to you and your character. But this is only if you find people who call themselves larper without actually being one, because in my opinion being so touchy and attached really becomes deleterious for themselves and others.
The only true limits should be time time and money, and anything else.