I made a verbal deal with a woman today about riding her horse. In exchange for a 1 hour lesson for her 7 year old son, she would let me ride her horse at a local Horse boarding facillity (We live in Alaska). I am 17 and I would be covered by their insurance (or my own insurance if theirs failed to be able to cover it) if there was an accident to me, and their insurance would cover an accident to the horse.
I asked this woman, and she wasn't sure, but I wanted to also use this horse to give a lesson to an adult friend of mine. My friend has ridden at another boarding place in the past and had signed a waiver (and i have one as well, though we'd both need new ones for the 2009 year), and she was saying that because it'd be "implied" that i was teaching my friend a lesson for compensation (even if I wasn't), that insurance may not cover injury to her horse or my friend (my friend has no insurance at all).
Can anyone tell me what the laws are about this? If my friend and I have signed waivers would this allow me to give my friend a horse lesson without risk of anyone being sued?
any help or links on this matter is appreciated, I don't even know where to start looking.

