[Zeatrix]

I feel this is an obvious c/r on the flop to let people know I have something and hence make them fold on the flop or turn. You don't want to encourage 3 other players to see the river when you only have top pair.

And one important note: Playing WA/WB when in a multiway pot is like asking to be outdrawn. You have to realize how many bad cards that can come on the turn or river and you need to either fold or eliminate the field. And eliminating the field in this spot is way better until the raiser or maybe even another player says otherwise.