So the question: Add your listing for free is basically harming the listing agent since the leads the listing agent deserve to get are taken away from him/her.

The real estate commissions care about license laws and harming the general public.In commercial real estate the REALTOR symbol really doesn't carry much weight.

I may be a little too eager and making an investment now may do more harm than good.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

I've spoken about the rental with one of our brokerage partners and there's no concern there; I'm a "no loose ends" kind of person, however, and would prefer to have something in writing should anything come up.Let me ask it a slightly different way--is there any harm in adding a liability limiting disclosure regarding my agency and brokerage to the lease packet?

Since they have a dog, I'm worried if the ant traps could harm it. 

The great deal here is that if the market has gone down or is stagnant you just walk away and the owner gets the property back no harm no foul.

Remember, there isn't any harm to put in any offer if it includes 7-10 days of due diligence. 

If you are in a W2 you do not like, you are likely doing harm to your mindset.

Some things to consider...detergents with phosphates, chemicals or heavy cleaners will harm the helpful bacteria in the septic system.