There are some practical concerns why I would not rent or loan out my TT:
1) Knowing how to tow safely is a skill acquired through experience. If someone is renting a TT, that means they probably don't own their TT. Which means little or no towing experience. If you rent your house out, the renters might do some damage but aren't able to uproot it and drive it into someone else's house or vehicle!
2) Most TTs are built so flimsy that you have to be extra gentle with the internal furnishings, etc. We are careful but still have broken things in our TT due to "lightweight (read cheap)" hardware.
If I ever did loan it out it would be to trusted friends for local area use, where I would tow it there and back for them.
Steve