If the application falls thru because of untimely or the lack of cooperation from the tenant, or any other wrong doing, I forfeit the holding deposit.

and as mentioned you do have responsibility for due diligence just because a seller might be guilty of wrongdoing your damages might not exceed your legal fees

Here's another article about PIP's alleged wrongdoing from Veritas News:Are Tax Lien Investments the Latest Real Estate Ripoff?

if you have solid facts of wrongdoing, I think any licensing organization is a first call for breach of any professional duties, and if it is outright fraud, a consumer site likely from  the attorney general or law enforcement would be possible, and a civil case could be pursued privately for damages....there are even more places for business complaints and reviews. 

Can I pass the fine on to the tenant if I can document that it resulted from their wrong-doing?

And of course the owner-in-hiding denies all wrongdoing.

And when something does go wrong, do I want to mess up on a $100,000 property or a $2M property. 

@Michael Healy assuming there's no evidence of wrong-doing on the Tenant's part, I would probably credit her one week of rent.I always think of these just like my personal home.

I figured as much that this was more of “scare”.I did reach out to by phone call and text message with no response asking for some references to my wrong doing so I can play “nice in the sandbox”.

Seemed like that *might* be what was going on at the Dallas REI Club but I could be wrong.