It's to fight against bots, right ? No more reason to it. You certainly don't want to annoy players with it by purpose. I believe you don't. So:

1)I select some messages and delete them => random event
2)I click to add someone to my friends => random event
3)I click on any other link, another random event, too many are there.

Leave them only where needed, divide pages between those where it is occuring and where it ain't. Nightclub page shouldn't have it, nor any of your profile related pages, nor gang/friends/messages page. There isn't a point to have them here.

Please, change it. It will only help - more happy players, less annoyed ones, 0 more bots. Everyone is happy.