From my experience, there aren't a lot of fair weather wrestling families out there. We are probably not the smartest group of people out there when it comes to the risk of driving in less than desirable weather/road conditions to get our kids to a tournament.
Sickness and/or injuries likely plays a significant role, at least I know that my kids have all been sick a lot this winter. I am sure it would be greatly appreciated if people would let the tournament know of known scratches ahead of time (if not a last minute illness).
That brings me to your final question, the competition. There is little doubt that a lot of us are looking at who is going to be in an upcoming tournament when we can see the list of wrestlers in advance. Again, rabid wrestling fanatics that we all are, I would like to think that seeing a age group/weight class full of studs doesn't make people decide that they have something better to do that weekend. Sometimes your wrestlers just have to take their lumps, learn from them, and hopefully it will fuel their love and respect for the sport even further.
I know that I havn't answered your questions definitively as to why there are so many scratches. I would believe that it is more likely that illness/injury play the biggest role (unless the weather is extremely bad, then weather would be a bigger factor). As for tough competition, you might consider a different sport if you find yourself pulling your wrestler from a tournament to avoid it.
