It damages the reputation of the bad actor, which means if another investor does due diligence, they will know not to work with this person.

I have received a property management agreement that has 12% of rents for price, (Seems high, but I can live with that) It also has a clause that basicly says Agent agrees to act diligently, but neither Agent or its employees shall not be liable to Owner or any person for any act or omission, negligent, tortuous, or otherwise, (except for intentional or omissions or gross negligence) of any agent or his employee, and owner agrees to indemnify and hold harmless Agent and his employees, and indemnify, defend and hold harmless against any liability, loss, damage, cost or expense, (including legal fees) by reason of such omission.

Every different dimension of REI has good actors and bad actors.

For sure there are bad actors out there.  

If you are talking about Ellis Act or moving in as an owner then that would not apply as there are additional rules regarding that.I know several people that buy out tenants, renovate the units and re lease at market rates in LA. 

My concern with accepting colleague requests from people who have not demonstrated any reason to do so is twofold:First, I may be associating myself with a bad actor.

He said yes..and to his bank account as well.Regardless of dealing with population that seem to have trouble advocating for themselves, I'm trying to figure out what I SHOULD and CAN do.Any suggestions that would make sense and not break the Ontario Residential Tenancies Act or upset the folks at the Landlord and Tenant Board?

Most will continue to pay the landlord rent, some will pay for the cost of the eviction, some will even pay for malicious damage caused by the tenant.

And there are only two possibilities, either you fail and never act , or you fail but you succeed by taking actions!

Not getting into religion, just the point of people thinking from an ethical stand point before they act or open their mouth.