I disagree. With software that works on top of client data the more hands on you are the better. Each client had "irregularities" in their data that have to be ironed out. With good access (and good communication) you can hopefully take care of "irregularities" before the client even knows they are there.
This is completely true, something that I'd like to note is that the more hands on your are, the better trust you build with the customer.
This means they are more likely to keep buying your product (they know you and like you).
They are more likely to come to you when they have an awesome idea for a feature that they want that would make their lives easier. (And you never say no to an ambitious request, you either explain that you lack the budget, or you try to redirect it into something that would fulfill the same need, but is easier for you to do, or you can explain how to do it with the currently offered software).
This is not just enterprise stuff either. Having a bunch of enthusiastic and engaged customers pointing out the holes in your software is extremely useful.
This all assumes that you have technical people who 'get it' and are looking to help satisfy the customer. I would never let an aggressive sales staff near them, however. It would be awesome to have something like 'contact a technical person to discuss solutions.'
