If things go south with the fiance before the house is complete it could really be a train wreck. 

Some of these include the high likelihood the homes are used as party houses, they are often in single family neighborhoods and wreck havoc in those neighborhoods when poorly managed (common).

I agree while the barrier of entry in terms of price point is lower, future increases in property tax can wreck havoc to the math.

If you are too dogmatic about the 2% rule it can lead you into some war zones that look good on paper, but don't turn out that way when you're tenants don't pay rent and then wreck the property and then it gets broken into and all the copper gets stolen... ask me how I know these things...

Your not going to wreck your own place or have to be evicted.

Family always complicates things and you don't want to wreck a good relationship for 30k, it's never worth it!

http://fortune.com/2015/09/25/housing-wall-street-investment/Got to say I saw this train wreck from a distance.

It is easy to have misunderstandings that can really wreck a relationship. 

This and my medical bills wrecked my credit.

If they have Other issues other than a low paying job they will always get a free gov't ride whether they wreck your place or not.