[alister]

You're quite right. I was thinking of an unsophisticated site owner with simple requirements (like a restaurant site) who hires a designer. He wouldn't know to put into the contract that all source code must be delivered. In such a case, he'd be better off if the designer used straight HTML. At least then there's a chance that someone else could edit it or maintain it.

[talmand]

Although I agree with the problem of the developer not handing over the source files, the same problem potentially exists if the designer doesn't hand over the source Photoshop and/or Illustrator files. Granted, that's not as big a deal as withholding Flash files, but it's there.