Website SEO for Google Places

Just a quick question for those of you who are helping clients with there Places optimisation.
How much influence , if any, does the SEO of the customers website affect there Google Places listing?
If you think it does effect it greatly how do you implement the changes if it is not you but someone else who designed and up-keeps the site.
I have heard conflicting reports on how this can effect the Places ranking although i have seen little proof in the companies i am dealing with.

I am a firm believer that it holds a very large chunck of weight. Not only in help boost your Places but also as a keyword pointer. I must say that this is more going off of research and not actual experience. Digging through several keywords and Place listings I can see the correlation.

Put it this way. I would not create a Google Places listing for a client and talk about getting them traffic if there website was garbage.