It should be legal to sue for knee-capping, unless it is knee-capping someone that is suing someone.
Frivolous law-suits are really hurting America, it needs to stop.
There are a couple things that could cut your court time down,,,,
Talk to an Attorney, skip the lawyer jokes, lawyers don't think there funny, and everybody else don't think there jokes. Look at any phone book and see how many Attorneys there are, and the sad thing is, there making some huge coin.
Get a clip-board and a read and sign sheet, the wordage needs to at least have local input from an attorney, but say something in regards to the inherent risk involved with saws and saw chain, could say that it is the operator to determine the safety and condition of resharpened chain,,,,,,,,,,
If everyone that signs the clip-board understands that they are relinquishing the responsibilities of mearly sharpening a chain, it may be all a Judge needs to see that there is no implication to altering (sharping) saw chain or the right to sue.
There are also a very few laws on the books that protect services as to the limit of liability, but a damn shame there are so many blood-suckers in the water. (<-----<<< very cleaned up version of the correct wordage there)