A couple years ago, my wife suffered a stroke. During my many visits to the hospital and rehab clinic, I noticed a number of wheelchairs that all had the same a broken part, which I saw could easily and inexpensively be fixed with a bolt and some nuts and washers. I went through about 4-6 months of dealing (mainly interminable waiting) with the hospital's volunteer coordinator's office, etc. etc. etc. The eventual bottom line was that could actually do some hands-on volunteer work fixing the wheelchairs - BUT- because I would not be an employee, they wouldn't cover any liability. I can just imagine a patient falling out of a wheelchair for an unrelated reason, and just because I'd once had my hands on it, I'd become the target of a greedy shyster. I told them no, thanks.
What I finally did was get the supervisor to introduce me to one of their techs. He took me to the floor where all the broken equipment is kept. Dozens of wheelchairs! I gave him the stainless steel nuts, bolts and washers I'd bought on my own, showed him how simple the repair was, and went on my way. It still bothers me.