This situation also demonstrates how all parties were forced to abandon their productive efforts (seeking new business ) as they were forced to devote their time into the non-productive time spending in defending their position from the accusations of the aggrieved owner of a defective property.....  

Again I have no clue as to your capabilities.. but that is what I have witness in my time here in Oregon and as a RE broker and one who has owned a few brokerages.

The window thing is going to take a witness. 

And I've noticed that there are some signs that signal you that an applicant might not be the best candidate, before even checking them out further.Now, you need to check out tenants' backgrounds, because you don't want to be accused of discrimination, but I tend to notice that when I see these signs, I find something about the tenant that disqualifies them as they don't meet my rental criteria.Examples:- Looks around the place for 5 seconds then immediately wants to apply. 

If you evict a tenant for a reason that has nothing to do with a protected class, you shouldn't have a problem with wild accusations thrown against you.

I downloaded a whole bunch of forms and this one "Addendum to Option to Purchase Agreement" calls for a "witness" to sign.

There is a lot of work to keep track of, but since I have witnessed it, I feel confident that I can manage everything smoothly.

A landlord could be accused of religious discrimination if s/he asks the tenant to refrain from having Muslim guests when there is no evidence of any violation of established property management rules.

It's also sad that I have to be extra cautious about who I rent to because someone may accuse me of basing my decision on race even though it never enters my mind.

Somebody wanting to sue for you backing out of a bad deal or accusing you of selling them a property with defects like unknown termite damage).