HI Marilyn, I've encountered these problems in the past and it happens no matter which CRM you're using. I believe the key is to show sales how you are creating marketing campaigns that help them sell better. If they can see this direct line they'll be more agreeable to following rules (as long as the interface is rather intuitive and doesn't suck too much)! At my last company this was the biggest headache I faced. We spent oodles of $$ and time creating custom layouts and dependencies that would makes sales more efficient. It only worked to a degree . . .BUT when I showed the correlation of marketing helping them break into named accounts and also aiding in their closed-won opportunities it was a *mostly* different story. Show them how bad data directly results in lost $$ and deals.
Good luck!
Vanessa