Bad idea. Even with a proper loan agreement, you have very little recourse if the borrower defaults, other than going to court. That will cost you, and will take time. Meanwhile, your Winny is being used and abused, and all you're holding is some paperwork.
VERY few people have the option of repossessing their property by themselves. They hire a guy like me to get their stuff back.
2017 Ford F-150 Crew Cab 4x4 3.5 EcoBoost
2014 Cruiser RV Fun Finder 215WKS
2015 Harley Road Glide Special in Amber Whiskey
2019 Mustang Bullitt
Yamaha Grizzly 660 (his)
Polaris Sportsman 500 H.O.(hers)