Well, they had an effect on the mulesing thing....they seem to be able to convince people they threaten markets.
And a group (not sure if it was them or another) has managed to scare my state government into not getting rid of a bunch of koalas which are destroying habitat on Kangaroo Island. (Small island off our coast which is a tourist mecca).
The poor koalas are not native to the island...got moved there by someone who thought it'd be cute...and they have multiplied enormously and are now busy destroying large tracts of bush.
They present a real threat to the ecology there, and will, of course, starve to death once they have destroyed enough bush.
Because so much of the tourist market is so nuts about their cuteness, the government knew it would be a problem just to kill them...so they tried a very expensive neutering program, which failed.
Killing was then discussed, and also trying to catch the little buggers and taking them back to the mainland...but there are plenty already there on the mainland, and they are very territorial, and hard to catch, and catching them stresses them a lot, and is very expensive, and they'd likely just die miserably....and a campaign began featuring lots of photos of undeniably cute koalas... and...well...they're still destroying the place while everyone wonders what to do.
A friend of mine is the biologist who publicized the problem, and ended up suggesting killing them.....he and his family got all kinds of death threats, and nasty phone calls in the middle of the night and such.
Not that the poor koalas have done anything except what animals do.