I disagree on the threat of retraction, obviously. Most firms aren't going to risk their reputations by rescinding an offer unless there was something severe (failure to disclose a felony) involved.

However, I think using post-offer leverage to negotiate extra pay is a bad idea. The leverage exists, but it's limited. I'd rather use it to get insight into (and favor in) project allocation than a measly few grand. Project allocation is the difference between having a successful career-- learning a lot, working with great people, getting the promotions-- and needing to find a new job in 12 months. A few thousand dollars is nothing in comparison. This style of negotiation is more subtle, and takes the form of a "reverse interview" than a line-in-the-sand "I want $10k more" statement, but I think the former is better at (a) presenting yourself well, and (b) getting you what you actually want, which is a successful career.

I also tend to subscribe to the philosophy that the first 120 days of any job (including post-offer negotiation) are an extended interview. What you want to show is that you care about your work intensely and that you have the potential to reach very high levels, but also that you expect to be challenged and given appropriate work; not that you are a mercenary who makes career decisions based on a few thousand dollars.