Is it ethical to visit a co-op and ask if anybody wants to join a different co-op?

I'm in a three person co-op and we're looking for new members. Advertising doesn't seem to work. Most players around level sixty seem happy to stay where they are.

I've been visiting other co-ops inbetween races to try to recruit new members and have been limiting my visits to small co-ops who might be interested in merging with ours. Would it be against some unwritten rule to visit larger co-ops to see if anybody is unhappy where they are and might be convinced to try something smaller?

I don't want to step on anybody's toes, but I've been in the situation myself where I was unhappy with how the co-op was being run and would have been happy to have somebody drop in to recruit me for a more suitable co-op.