Hey @Zach Edelman, so there are a bunch of ways it can south depending. I will give you real world examples that crushed some "investors".
Pandemic rules in some states were clearly a problem for many of us. Arbitrage people we unable to get anyone staying and had to pay above market rates for their leases. Not enough cash reserves and done tom turkey.
Restrictions going in place. You need to live within 50 miles of a unoccupied STR, you need to be living there, lottery system for new permits and you don't get one, STRs are banned overall in certain zones, HOA votes to disallow STRs. These are all examples of how you can lose. All of this is out of the arbitragers control.
Regarding the cash outlay, you are forking over thousands of dollars. Let's say you find someone who normally rents a nice condo for $1750 a month. You agree to pay $2000 a month. So you have first, last and a deposit. Let's say all that is $5000. It is a 2/2 condo of about 1200sqft.
Now add in full furnishings. In order to be successful, you can't really skimp. I am a big proponent of looking on Craigslist, FB Marketplace and OfferUP for deals on USA made furniture. Even doing that you are going to be in it for about 10k all said and done and that is on the cheap...if you get lucky. More if you just call Wayfair and do it all there. You need furniture, linens, appliances big and small, cleaning stuff etc. The list is long. Some estimates are $10 per sqft, some say 10k per bedroom.
We started from scratch with our 2700sqft lake house. Nothing was left except the fridge. I was living on those classifieds sites snapping up whatever I could find that looked great and fit the comfortable family home style we were shooting for. A lot of stuff we got for free. We were still about 25k all said and done and I really worked hard to get the price down.
That is just the things that come to mind. What if you are doing great. The owner of the property is seeing it and decides not to renew the lease and do it themselves. Then you are stuck with a place full of furniture, linens etc that you have to move out and store or give away (to me) and you have to start over.
I am not saying it is a bomb, but to say it is low risk is just incorrect. It isn't an investment at all as you have nothing. You have the stuff you bought. Which is depreciated to next to nothing.
The reason I come down hard on these dreams is most of the folks who ask about it have nearly zero dollars. They can barely afford to rent the place let alone furnish properly.
Most owners are getting pretty savvy on this so if they do decide to allow it, you can expect to pay above market rates and a larger deposit. You will most likely be responsible for repairs (within reason) and maintenance. You might also have to give the owner a percentage of the gross.