We have done it in the past but it turned in to a bit of a nightmare dont forget you are liable 24/7 we even had a couple of scooters for rent, we got rid of them.
What we do now we still offer car rent but we use a local company were we get paid commission they are liable for that car, Im not getting mad phone calls in the middle of the night, Lost keys and things like that.
We have guest now who wanted a car for 25 days I take him down to their office, he signs their papers pays them, thats it done.
For us there are many ways to produce extra income, One of the favourites here is boat trips to the other islands we get paid 30% commission from them, The guest love it because they get picked up from our properties and brought back,
Hey even the hospitals pay commission here hahahaha,
I have a list of local restaurants that I recommend then I get a big discount when I send customers my husband gets a couple of Free beers.