A slippery slope is fallacious if there's no argument for the the progression down the slope. Lots of valid arguments take the form of a slippery slope.
In this case, there is in fact an escalating progression of bad things happening in Airbnb rentals; in rough order:
* Criminal enterprises buying entire buildings and turning them into unlawful hotels
* Renters trashing Airbnb rentals
* Floating brothels
The leap from here to "gambling" doesn't sound too crazy; in fact, gambling seems more innocuous than a floating brothel.
The point is that any inconvenience to neighbours from such a 'brothel' is hypothetical - nobody even noticed that it was there, so they definitely weren't harmed in any way.
There isn't anywhere near enough information to ascertain whether neighbors noticed.
I have no idea who my neighbors are. If they weren't actually here, in the building, I'd have no way to contact them whatsoever. That doesn't mean I don't notice Airbnb tenants.
Illegal gambling is hardly a problem anymore since there are so many legal places to gamble. I think she just picked a random item from her mental bucket of "things that sound scary and bad".
In this case, there is in fact an escalating progression of bad things happening in Airbnb rentals; in rough order:
* Criminal enterprises buying entire buildings and turning them into unlawful hotels
* Renters trashing Airbnb rentals
* Floating brothels
The leap from here to "gambling" doesn't sound too crazy; in fact, gambling seems more innocuous than a floating brothel.