Thanks for the replies. Interesting to see that this goes on at quite a few places. The one and only reason that I'm still working here is that it's only the mx guys who give us a hard time. While management may not be too happy about cancellations, I've never been pressured by my boss to fly a plane that had something wrong with it.
There's an interesting article about this topic in this month's (Oct 2008) AOPA Flight Training magazine on p.41 called "Everyone's been doing that".