While they do eat into rental margins the larger profit came from the sale and the added rental profit was not worth the hassle of being a landlord.

I've even heard of GCs using auction type settings for returned items at Home Depot and Lowes for steep discounts.I've learned a lot about the GC game as I was up close to over 40 projects last two years and some went well and some did not and when they did not it was all Contractor related.If a GC isn't sourcing cheap materials at the same time milking the hell out of his 150-200 per day workers, then you can find yourself eating into your margins real fast. 

If you are only doing a 1-2 year lease option, then I'd recommend you just buy down the prepayment penalty to 1-year and just eat it if the borrower executes early. 

It may even eat into your vacation.

Skip the vacations, skip eating out with friends.  

As the owner, you may want to eat the cost since future tenants will likely make the same mistake.

The buyers need (not request) a full 5%-6% seller assist and become complete menaces and eat into your margins with lengthy repair addendums following inspections. 

Always pay them back and eat the loss yourself.

The contract healthcare providers are always looking for some great MTR options close to work but also close enough to good eats, MARTA etc.  

They bring more stability and less turnover than STRs, but the discounted rates and occasional deep clean can eat into profits.