I have noticed the warnings about justifying the price based on the ability to raise the rent, possible appreciation, better management, etc.  

You and him will both learn something new and valuable from each other. warning: If he quits for a while and maybe one day you smell it on him but otherwise he's making payments on time.

Definitely check out the podcasts (warning, you might get addicted and use up all of your data plan!).

The short sale addendum has language that warns all parties of the need to get creditor approval and the fact that the sale may not go through and that if it does that it could take an extensive amount of time to do so.I'm finding that less and less short sales are being approved these days.

I've heard warnings against purchasing near campus due to the large number of student housing developments of late.

I will warn you though that the site is addictive.

Interesting what's going on across the pond in our area of interest. http://www.bloomberg.com/news/articles/2015-10-12/flipping-frenzy-grips-sydney-spurring-warnings-of-housing-risks

You should be very stern about it though and probably start the eviction process.Is this tenant also behind on rent, by chance?

One of my favorite features are the podcasts that have interviews with successful investors and others in the business to show give tips and warnings without a ton of hype or a sales pitch. 

I remember 'economists/experts' warning in 2009-10 about inflation when QE started.