I've been in several "new business" meetings lately where I find myself being sold by the person who I, conventional wisdom says, should be doing the selling to. After all, I'm there to sell them on my services!
This usually happens for one of two reasons:
1) We have done a good enough job of demonstrating how we can add value, that the prospective client REALLY wants to work with us; or
2) The "prospective client" wants something for nothing and is not a legit client at all.
The trick is to differentiate the two.