I wrote off almost $10k on my taxes last year in legitimate charitable donations from things abandoned in my properties. 

You have a legitimate concern.

It's also available for download from the BP File Place Documents]People who fraudulently attempt to bring their pets into their rental home, in the guise of being a legitimate assistance animal (service animal or emotional support animal), often will drop the attempt as soon as they see I'm not so easily fooled. 

Here we have a substantial response by someone who, yes, is selling real estate education in another venue , but is also willing to contribute something substantial here o an open forum.This allows for substantial give-and-take. 

How can I know if I’m being scammed or if this is a legitimate opportunity?

It sounds like other than being "annoyed" at their spendy lifestyle, you don't have any other legitimate complaints about them, so you have to look at this from an objective, emotionless place. 

For pure short term rental, further Southwest Austin has a ton of wedding venues with hill country appeal that also do well in peak season for rentals. 

Wedding planners are usually looking for venues to host their clients so this could be another option in their portfolio. 

It would be great to get together and do a socially distanced sync, possibly at an outdoor venue.

It can legitimately hurt your offer in a competitive situation.