With weed, you run into issues of medical marijuana and people making claims of medical necessity.

Depending on the location in NY there will be a different tolerance "strictness" when it comes to following the eviction procedure.

Maybe you're just not ready for this type business or could find a way to figure it out on your own.Alternatively, look at medical doctors.

So the county at some point is likely to take a bigger chunk with the stated purpose of offsetting the increase in emergency medical response. 

Yes, one can, but the procedure is complicated.

A bankruptcy that's not their fault, medical bills, foreclosure all could be reasonable.

I think in VA if it's in question, I have to post notice that tenant must notify me in writing within 7 days if they intend to stay and if no response, I can assume it's abandoned and follow next procedures for turnover and security deposit. 

Unless you have large medical bills it's not going to make sense.

So going over the lease and the duties and responsibilities while we sign it is part of our onboarding procedure and tenant training!

Assuming they're refusing to pay, pore over every detail of your lease and proceed with exactly the processes called out by it (and get advice from your lawyer concerning State laws/procedures to follow in case they may trump your lease terms).