I think this kind of thing makes people feel like you're pushing a message, to which the automatic response is to push back.
What I've found works is to be agreeable, inviting, meet them at their own values and present how it as a hard problem to solve which isn't being competently tackled by this other dumb group (not us, we wouldn't do this). 
That kind of thing. Had a 100% success rate so far.
I'm simplifying my approach, since I'm not spending a lot of time on this, but if you imagine I'm not a dumbass and think about what kind of approach like this could work a lot, while not being dumb in that it doesn't actually address the problem, you'll probably get what I mean.