Personally I would stop the bleeding and tell them they either need to catch up or move out. 

Don't come off as a corporate stooge who wants to bleed them dry.

#s may look good today, but you might bleed out slowly next 5-10 years.Something to consider depending on your life situation (e.g. busy professional/w2 worker who may find better returns climbing up the corporate ladder while creating this on the side).

DO NOT, I repeat DO NOT let them stay hoping you can get the back rent, it is gone, you can only stop the bleeding going forward.

Appreciation has worked out so well over the past years in the Bay Area that this buyer was willing to either bleed ~ $1500 a month (if he got a mortgage), or take a sub 4% cash on cash return (if he paid all cash), to bet on prices going up!

Me personally, I want to reduce risk to my business, and thus in the long run, reduce the bleeding points of money from my business. 

The welfare pimps and bleeding hearts have not done anyone any favoures.

Encourage you to "read till your eyes bleed" in multiple facets of investing on BP, as well as connect with other BP members and network with local REI groups.

I dont want to bleed from negative cash flow and use reserves, but I also dont have to immediately run and sell at the first sight of a down market. 

I assume this is hot water and not steam. it probably just needs to be bled again - air can get trapped in the system and continue to show up for awhile at certain radiators. its also possible the water pressure in the system is too low if it is manually controlled and not adjusted after bleeding the radiators. this can impact upper floor radiators.