The seat clamp on my cross bike is giving me some trouble. About a month ago it loosened up at a cross practice pretty much on impact of a flying remount where I displayed particularly bad form (even by my own low standards). At the time I was sure I had stripped a bolt or the threads the bolts go into. I took the thing apart and I couldn't see any damage to any of the threads and everything threaded together smoothly so I just put it back together, tightened them down and rode it.
I had no more problems until last night. Riding the course at a local park I noticed my seat making a lot of creaking noises at the start of lap 2. By the start of lap 3 my seat was sliding front to back pretty freely in the clamp. Again, I took the clamp apart and inspected the threads. Everything looks good. The bolts screw in easily and don't seem to have any play in the connection.
Is this just something that normally vibrates loose occasionally so I need to tighten them down regularly or is this an indication that something is screwed up in the clamp and I just can't see it?