It's pretty much impossible that there would only be two situations where a tenant didn't pay in a low end unit - and all of these are located in very low end neighborhoods. 

If somebody is just looking to read introductory information on flipping, then FlipSystem would not the best fit, but if an investor is looking to actively begin flipping out of state and focus on base-hit micro flips like I discussed in my recent Bigger Pocket podcast, then our program provides immense value that is unattainable from a low-priced resource such as just a book or recorded video.As you mentioned, flipping houses should always be done with caution and careful consideration.

You can get into it with relatively low money down depending on what options lenders offer in your area. 

Thats a good plan, retail vacancy is super low!

You lost that money because it couldn't be appraised and the same sq ft if it was heated would be worth $200 per sq ft at a minimum in any market which is $80k swing.

If househacking is possible I would rather buy my primary house using a low down payment for first-home buyers than invest in other properties in Sacramento, Modesto, Fresno, etc.

Meaning that even with cap rate expansion set to 0%, the sale price is lower than the going in purchase price. resulting in negative/low yields.Am I missing something here?

So it really is going to cost you as low as 20% or as high as 47% depending on your tax bracket. 

Inventory is so low and hard to find deals.  

The DC area is an incredibly low risk market.