No it wasn't that, the contract specified I couldn't work in IT consulting for 12 months afterwards, had to give 6 months notice, and *ANY* outside work (not just IT) was unacceptable. The 2 days a year I do IT consulting (i.e. helping sort out a website or putting together a PC for someone were classified as consulting, so would have been in breach of contract for looking at a computer).
Edit: and that contract was a long way from being normal.
Double Edit: The sticking point was the company would not let me invest my own money with another company, regardless of what market the investment was in. It was an outrageous and unenforceable clause to the contract.