You must have a lot of uncurrent people coming down to jump Nov-March. I know when I come down to a FL DZs I jumped till I had to catch my flight. If a renter has a cutaway at the end of the day he/she may need to (or want to) leave to catch a flight home. This said in the rental agreement I would outline that they are responsible for retail cost of lost gear, repacks, cypress fires, and or recovering the main / free bag (does not matter who packs it). As long as your up front and the terms are not buried in two pages of legal paragraphs you should be good..
After the fact you should in good faith charge them what it cost to get the rig back on line. Used main, recovery cost ex. , but legally have them on the hook for the worst case.