The agency that does Section 8 in my area said it happens "occasionally." 

Which we do occasionally. 

I have lunch with them occasionally and I always ask them if they can both quit their jobs and retire after five years of investing in multi-family apartments with lifestyles.  

I've been able to figure out how to manage remotely with occasional visits.

Because of the legal structure of a CO-OP, they seem to have more 'discretion' over who buys in, and IF they allow renting.I've had the same thing occasionally happen in Condos.Best approach: DYOR and make sure you understand the process for the particular building you want to buy into.

You want to create a strong & trusting relationship with your lending contact, but occasionally looking at different options should not be discouraged.

You can occasionally refi one instead of selling it... then the money that comes out isn't taxed, but you have to slowly pay it back in.

If you have family in an area, where someone can just drive by occasionally, all the better.

In addition to Gordon, check out Dave Van Horn who occasionally posts here on BP. 

I occasionally have some off market opportunities, are you interested in more deals?"