If he has cash in the bank to be able to cash out the underlying note in case the it is called, then I suppose he could play the cat and mouse game. 

City may have ordinances regarding that also so you could site that rule. but basically if it's done inside the garage on his own personal car I would be fine with it as long as he has taken care of oil waste and puts down protective mats, If his car dripped oil on the driveway.. would you have a fit or what ?..

Anything with the little blue dot lines under the word will display a definition if you hover your mouse over it. 

A mouse can be standing right next to an elephant but just because it is right next to the elephant the mouse is certainly not the same things as the elephant and with real estate properties can be very different even if right next to each other. 

If your low paying restaurant tenant decides to shut down when you raise rent then you should be able to market the property for restaurant use as well as daycares, laundry mats or any other zoning that is allowable.  

@Ryan HowardI can respect you getting out there and finding vacant homes a little tactic i use to find properties is called "google drive for dollars"I simply take a target zip code/street in my investment area and begin to use google maps to walk up the street using my mouse to zoom in on any property that may look distressed.

@Enrique SelmanHover your mouse over his name.

Mouse over any underlined word for a definition :) (this one is real estate investor association)

This way is someone sues you it would be a game of cat and mouse.

@Mat Deveaney I think in your state you need to go through an attorney.