I took it as a red flag and moved on. 

Thanks,Matt This shouldn't be an issue unless they are significantly above the "Market Rent" might get flagged, but in most situations not likely a problem as long as the leases are clear. 

Are thier any rules against this or is this something that the underwriter might think is a red flag?  

Are there any immediate red flags that you avoid?

Are there any emerging opportunities or red flags?

I used Zillow to list my rental and accepted someone's application however after my few interactions with them on the phone some major red flags have come up and I wanted to know am I under any legal obligation to rent my property to this person. 

And when it comes to a company pressuring you not to do your due diligence, that should be an enormous red flag. 

I’ve noticed a few areas of concern (or red flags) during my research that I’d like to verify after digging through forums.

I would suggest to speak with a broker or someone familiar with the process and have them review a full package and try to look for any possible red flags in advance. 

I would definitely have a red flag raised for future dealings with this tenant if they didn't own up to it.