It's nice to say that they'll stick with you but that could change in an instant. Plenty of stories out there where people have gotten screwed over by unscrupulous VCs.
PS. obviously, there are exceptions to the norm but I'm a big believer in understanding people's primary motivations.
I think the key is knowing the parties with whom you're dealing and knowing their past behavior. I advocate reference checking portfolio companies that failed: see http://www.bothsidesofthetable.com/2010/02/08/how-do-you-ref...
So given the complicated web of legal documents from the exits of folks that have been screwed over, how would you find the worst cases?
This is an analog situation. Things like this are a matter of degree not absolute. Just like speeding, insurance claims and taxes. Some people can definitely be trusted less than others to care at all about the other party. Those are the people that you need to identify.