Go and knock on their door, bring some cookies or a bottle of scotch find out what’s up and bring your tool bag of exit strategies with you so you guys can figure out a plan that works out for the both of you!

His tenant, who can now only afford a $1000 a month apartment, comes knocking on your door...I know that this scenario needs to have a somewhat more financially diverse group of people, but I think this is what could happen

I knock them down and build new at a cost at or under $200 per SF where the resale is $600 per SF or more thereby “creating a spread.”So good deals don’t just appear on the MLS or anywhere else, one needs to create, negotiate, and work to make them deals.

Knock first then enter with your key. 

Even with an FHA you should be able to get PMI knocked off IIRC.

Go knock on the door, explain the situation, explain it might cost you business, and ask that it be taken down (and not used as a curtain).I have seen a tough guy approach to dealing with a flag issue backfire into a very stressful uncomfortable mess (for the manager) when it's not in the lease, taking a few months to resolve by eviction for unrelated "stress issues".Next lease have a no flags/banners put into your leases--and explain to the complainer that's how it will be handled if the person doesn't take it down.....Easy peasy. 

When they're worried about folks calling and knocking on their doors, asking if they want to sell their homes, I remind them that Realtors and investors alike are looking for homeowners ready to sell.

Some would suggest TenantCloud, Tellius or other apps which allow you to process rent collection; but, there is an option out there which allows you to collect rent much quicker than those others but still provides other rental management tools you might find valuable (again, not to knock Cozy or these other tools like Zillow rental manager), but you can easily go with an option that will help you keep track of who paid what and on which date with a tool that is reliable and fast.

I can just set up 2 15/hr guys on the quikpoint and knock it out in 2 days with them.

Recently, the tenants started complaining of loud noises in the walls and air ducts, stuff being knocked off counters, and chew marks throughout the kitchen.