More money chasing the same amount of or even fewer resources devalues that dollar, thus, you get runaway inflation.

First thing Id check is if they raise the value, devalue, or have no impact on your properties value in your market.

Again... don't worry about the fees or the gold devalue if it happens to you.

What is the chance for devaluation? 

Does it de-value the home to register with Section 8?

I want to invest 500k real estate somehow to protect against dollar devaluation.

The Unethical thing that you could not do that may be considered illegal is if you in some way destroy or devalue the property since it is an asset to a senior lien holder and they may suffer as a direct result if you do any damage.

Because you're paying the loan back with devalued dollars, and inflation adjusted income while expenses are fixed. 

I am reading on forums these assets have been devalued 75-90%.

Although it is strange that other countries are looking to China, who devalued their currency just a few years ago.Many forecasts I have seen look at a few indicators, but as you can see, there are many other pressures at work that could help investors, but could also cause a recession, or depression, if they fail in a big way.