I have 2 homes on the Eastside - AC unit was stolen before tenant moved in (thieves climbed a 7 foot fence), attempted break in with the other house (alarm scared intruder away). 

I warn all tenants who give me whatever story on why rent is late or going to be late, that they will be getting a POQ notice on the 3rd day and a late fee on the 5th, I don't care if it's because their employer burned down or thieves stole all their money or their grandma needed an emergency appendectomy.

Caliber started picked up the loan and it was sold into this lsf8 master participation trust as a security trust services by them even though it showed security trust was closed for almost three years when my loan, being the only one ever to be able to be out into a security trust AFTER it closed because it cannot be done, and they are the most unscrupulous bunch of thieves ever seen.

Your gang of thieves (and it would take a gang) might have better odds  of success knocking off armored cars at high noon or kidnapping wealthy children for ransom (a crime with a near-zero success rate in the developed world today).Get the case number, contact the USPIS independently, see if this rent heist story isn't really a snow job. 

Would it be possible to file a mechanic's lien on your own property and would this be a way to discourage potential title thieves?

I didn't mention this part but my AC unit was stolen right before the tenant moved in - the thieves climbed a 7 foot fence.

They will allow tenants to stay without paying full rent and your properties will get trashed.2) Thieves who will lie, cheat and steal from you.

A main target of these thieves/squatters are houses being listed and sitting vacant.

they are more expensive than stick built take years to get approved through the building  departments in many jurisdictions and the folks that buy them are eclectic to a certain degree.. they work well in Rural settings where you can really lock them tight and leave and not worry about thieves.  

NOT in any way saying you are.. but you get the point I am sure.. your tenants are your life blood so keeping them happy is more important than letting buyers who are not even in contract into the houses just to look around not like it and not buy it.If the home is vacant I suspect they are Leary of squatters and thieves and or they have been burned by wholesalers and their lies about having their partner look at the house.. which is really not their partner but is potential buyers.. very slimy how they do that.