Turned out their party planning business was a call center for prostitutes. 

I had an apartment that had some pretty serious drug use and trafficking, along with prostitution issues.

Anita Anita,There are many forum threads here on BP about areas but here's my take on it:A - location where you and I (and everybody here on BP) want to live in (very low crime, no houses or apartments with boarded up windows, schools are the best in the country or best in the state or best in the county)B - a grade below A, this is where the middle class lives, good school district, still low crime rateC - this is lower middle class, higher crime rate, schools middle of the road in terms of rating, rarely do you see a house/building with boarded up windows but it happensD - clearly lower income area, very high crime rate, one house per block is boarded upF - this is called the WAR ZONE, every other house is boarded up, drug dealing and prostitution happening in every other corner specially at night, graffitti galore and even the police is afraid to go there because this is where 90% of violent crimes happenI started with Fs/Ds and I thought I went to heaven when I got Cs.

Drugs, gambling, prostitution all pay in cash (I have had all the above submit applications).

i have personally never had that offer when it wasn't to compensate for some sort of red flag, ie: past evictions, felony conviction, sex offender, drug dealer, or prostitution/porn But who knows, there's a first for everything!

I went to their office a few weeks ago and spoke to the lady that handles the fifas, because I have a house next to one of mine, that is full of prostitutes and drug dealers and it's still in the name of the deceased owner and her taxes are $ 30 per year or so.

@Brian Gibbons  the reality of unlicensed activity and much of it advertised on Craigs list is one day.The authorities are going to do exactly what they do to Prostitutes. 

Well, unless pimping and prostitution is a federally protected class I'd skip these applicants!

Dealt unusual problems like prostitutes, overdoses, break ins, etc. 

OK, hearing all these stories makes me wanna jump on the train - I've heard "talking" about it helps ones overcome the trauma ;/ - I had a tenant illegally sublet a unit in one of my triplexes to a prostitute/crack head.