I've been there before, to the tune of a $10,000 "loan" to an in law for a small business that ended up turning into a gift after just four payments.  

I'd consider you lucky to have been left such a gift.

But as a hobby why care just let it go.If your rentals are being operated as a business why would you gift someone money they are not entitled to. 

I often wonder if it's worth it to have exceptional customer service / rewards for tenants, or if you'll get stepped on.Example: Anyone who pays rent on time for an entire year and renews the lease is gifted a $100 walmart giftcard (I wouldn't advertise that though, just a ''surprise'' reward)

My wife is a licensed realtor and manages apartment buildings for a living.Did I mention that all my tenants get a gift card for Christmas, even the ones that are late, even the ones with arrears.

In return, I gave my tenant a little monetary gift towards her move out expenses.

Our "all-stars" receive special benefits such as having their unit upgraded first when we do upgrades, special requests are more often accommodated, and occasionally we give them a special thank you gift.

You might consider two tiers of gifts.

I even gave them 25$ discount on the monthly amount if they are willing to sign a 2 years lease instead of 1 and send them gift card on thanksgiving!

We also give tenants a canister of disinfectant wipes with their move-in gifts, so they can tend to matters on their own.