They were moving from out of state and overnighted me the signed lease with the security deposit, that equaled one month's rent. 

There are 2 camps basic camps of naysayers; 1) those who are risk adverse, 2) those who are jealous.  

For us, the problem when the crash first happened, was because many people lost their jobs and had to move back "home" or in with family until they could find another job.This left us with about 20% vacancy almost overnight. 

In the Bay Area it's standard to limit overnights to 14/month (seems to derive from SF law), and any more than that requires the other person to be on the lease as well (where you can charge that extra $100).

The yards would be taken care of and a maid service would clean the main part of the house once a week.There is a strict policy of no overnight guests and no parties in the contracts!

As long as the college/university is going strong, there will be tenants who need housing.When I was managing a 26 unit building in Silicon Valley, and the market crashed, almost overnight we lost around 6 or 7 tenants. 

I don't see anything wrong with these boot camps in teaching/explaining the  tenant/landlord laws. 

@Joe Villeneuve  my comments are more directed towards the camp who's motto is" I just want cash flow and appreciation is icing on the Cake"  but its all a personal preference and risk tolerance and historic movement in RE values.And when your born and Raised in the Silicon Valley like myself and started in RE in 1975 I have seen the huge run ups.. so of course I just can't have anything but an appreciation bias for sure..   1975 home in Cupertino were I was raised my parents paid 25k for it.. today its worth close to 2 million and its just a Valley track house nothing special 3/ and 2 with a bonus room and 2 car garage on a 6k sq ft lot...and what you don't have in the bay area is with the very very tiny exception you have NO area that devalued at all...

Overnight mail? 

People don't usually become felons overnight....but when they do get caught and charged, it is just something I'd like to know.