@Cathy1096
Cathy I am not a legal practitioner and have no legal qualification to offer qualified advice but, my feeling is, (particularly as you are a resident of the USA in Illinois) it would not be prudent to let guests use anything of yours that they can use in a public space.......away from the boundary of your property!
US litigation laws being what they are it can be argued in a court of law that the equipment, be it pushbikes, jetskies, roller blades, Ebikes, yes even canoes and Kayaks were not maintained in a suitable condition for public use, and further the use of such devices formed part of the paid rental agreement. If they weren't staying there they wouldn't have access to them!
Cathy it could be a can of worms, guests do stupid things when they are on holiday and although I am not in the US, I wouldn't do it here in Australia.....and we are much more relaxed with regard to litigation than the US.
I wouldn't want to see you and Robert get stung!
Sure, get proper legal advice from your insurance company, not your broker. There is every probability your insurance public liability would cover you on your property (provided you have short term rental insurance), but not on public space.
As a fellow host, Cathy I wouldn't do it!
Cheers........Rob