How to counter-troll Greenpeacefags?

The last couple weeks, as I've been walking the eight blocks between buildings at work in DC, I've been approached by kids in blue T-shirts asking me to participate in a survey or whatever. Well, I just noticed last Friday that they were actually with Greenpeace.

How would you guys scare these kids straight before they get recruited for full-fledged eco-terror?

Trolling is never acceptable!