Part of the “Homeland Security thing” You know, drugs, terrorism, etcYou can be sued and criminally charged for up to 7 years after the transaction.

Most US prescription drugs can be bought over the counter from the Pharmacist. 

., being a nuisance to neighbors, use of drugs, taking in new people without consent by the landlord, changing the locks,  or modification of living spaces without permission?

In Mexico, that won't happen; you'll be shot if you get involved in the drug business, which most people won't do.

@Matthew Morrow I had a house it was a drug ring and couldn't evict for 6 months.

Imagine someone harassing your girlfriend, damaging your property, using or selling illicit drugs, dog biting you or your other tenants and creating a flea or noise issue, or any number of other potential issues.

I am really just looking to avoid the worst of the worst areas (anywhere with open air drug markets or active gang warfare / prolific violent crimes).

When going before public meetings with your proposals, drug, alcohol, and half way houses for former incarcerated, receive the most scrutiny.

Or, the actual location could be terrible (like ghetto or drug area or war zone).

But that's me.To answer your question, I'm not in the business of recycling dirty money but I think it's pretty well known and established the the proceeds for criminality and the drug trade is invested in all sort of business, especially real estate.