Had a tenant once whose cat ruined the carpets.  

Those people ruin for the rest of us.

When judging a dog, I look at the potential of them ruining my hardwood floors, destroying my backyard, and tearing up my door jambs/doors.

Our king size foam mattress soaked up all that water and got ruined.

But, your applicant's reason is that they chose to ruin their credit and let their property go into foreclosure, rather than keep their credit intact, and sue the partner.  

However, I know I wasn't going to ruin my credit now was she even though things got very uncomfortable.

I also have hardwood floor's in my properties that are quickly ruined by large dogs.

Ask yourself what you would rather see when you look in the mirror: a person who collected "their money" at any cost, or someone who wished a cancer patient well as they embarked on the always hard, usually uncertain journey of starting cancer treatment.I know which choice would allow me to look myself in the mirror and still respect myself.

The question I have is, is it worth it to ruin a previously prosperous relationship with AirBNB over hopefully 6-8 weeks of rental income?

i could be ruined.