Everything Paige said and a few more.All vehicles must be licensed, tabbed and operableNo water beds, pools, portable heaters, portable dishwashers, portable clothes washers or dryers shall be used on the premises without prior written consent of agent/owner.No dust, sand, dirt, rubbish, coffee grounds, feminine products or other foreign material shall be flushed or washed down toilets,sinks, or wash basins.

When I use to travel extensively, I carried one of their small portable scanners.

Tell them to get a portable humidifer

For the sauna and a couple of closets - where it isn't apparent if the light has been left on - I installed switches that glow with a red light if they are left on, prompting folks to turn them off.If you have an old hot tub, look into replacing it. 

@Tom CamardaYou can get a portable air conditioner/heat pump that is rated for 400-500 square feet for $250:http://www.newegg.com/Product/Product.aspx?

Portable heat pumps work pretty good and I like ductless heat pumps and the higher seer models will do better in winter.

Then of course there's wine cellars, fire pits, saunas, the list is endless.

While a CMHC insured mortgage is portable, CMHC homeowner mortgage loan insurance is available on a maximum of one property (1 – 4 units) per borrower/co-borrower at any given time.

I also put in portable units in one of my really inexpensive houses in MI - cost ~$450  and the tenants love it, so I'm going that route for any future MI properties.  

Are portable garages any good?