DMonDude

I do a similar thing when i do local hotel stays as well. I can only host when i go to a hotel for a weekend every once in a while and i like to make it count. So i will shotgun message a handful of providers with the idea that i want to at least see one guy a day i'm at the hotel. So if one replies first and nabs the friday night slot, the guy who replies second gets to choose between my saturday or sunday night slot if they're available then. Rather than being told "nevermind i already booked someone else", which is where it can feel like we're wasting their time. So if it works out, great! If it doesn't, it's a scheduling conflict with the door left open to try again later (either at their place if they host or next time i get a hotel), and not because another provider swooped in and stole me.
But more often than not, when i'm looking for a one off in-call. I message one preferred provider at a time and i wait for the reply and confirm the booking or that it isn't a match with them before i move on to the next one cause there's no rush on my end in that scenario.
So it's ultimately a bit of both for me.

Actually i just double checked. I don't think you can send attachments that have to be downloaded on RM (unless it's a zip file maybe?). Any photos open within the browser (and not as a pop up window), and when i checked a message thread that had provider pics in it, they all did open with a blank page for like a split second before showing the pic. I think it's just a loading delay. They open instantly when i re-open them after that 🤷‍♂️

I would imagine they'd probably/maybe tell some of their longest time regulars they were retiring (just so they know or maybe even get a "one last time" in), but for the general public I'd think they would just delete their ad and vanish.

From my experience everyone does Zelle, Venmo CashApp and PayPal now mainly. I'm sure any provider would still take cash if you asked/let them know though. I can't imagine any would would turn down the cash.