Bumping a club does nothing unless people are looking at the all groups list. And hardly anybody does that.
Well it's supposed to bold the group name when people are on the regular group page, in which case I hope they click it in order to see what's new.
Unless they are in a billion groups like me...
I'm in more groups than you, and still check for bolded groups on the social group main page :3
I generally only look at a few of my own groups for updates.