Keith, I'm generally not asked for a liability waiver but just last week I asked a contractor about hunting a lot where he was constructing a small commercial building. There had previously been a house on the property. He had no problem with me hunting the property but asked that I fax him a liability waiver. I was glad to comply but did not have a sample waiver so I just made one up which I will share with you and others for what it is worth.
Dear Mr:
Thank you for your time this morning and your consent to practice my metal detecting hobby at your job site in the 300 block of --------------------------------here in Lakeland. Please be assured that I will treat the property with the utmost respect and will obey and observe all national, state and local laws. I only dig small holes, (approximately three inches in diameter) and all will be refilled. Any trash or litter retrieved from the hunt will be removed when I leave. I will not metal detect at any time your workers are present so as to not interfere with your business activities. In addition, I will not hold you, your company or the property owner responsible for any harm or damage which may occur to me while on the property.
Thanks again for your consideration and good luck to you in your business endeavors.
Sincerely,
(You may want to use parts of this and modify other parts to conform to your particular situation or you may want to pen your own waiver.) HH
FL Junkman