Yeah...but hold on now. OP is spreading the word of a potential grift where hobbyists are getting ripped off for their deposits. If you've seen Rene before, you know that's not the case here. I've seen Rene many times, and she's top notch. She's also catering to some specific niches.
I can sympathize with you on a couple points. Her rates have increased, sometimes don't line up across ads/sites, and the deposit is more about securing the hotel rather than vetting a new client, so it's still expected from repeat clients. Maybe she's been burned by pre-bookings that cancel when she gets to town and swipes a credit card for 3 nights? Who knows? All of these things have not caused an issue with me booking. I do not judge, and these things may bother others, and that's fine. My recommendation would be to not see that provider. Nicely pointing out the difference will hopefully get the discrepancy resolved and avoid that with other people, but obviously you got the vibe that you were going to have to pay a little more than you thought. It sounds like it came down to $100 over her p411 and you pushed back again over $50? Did you check in all spots and verify what her website has posted for rates?
We're in a tricky hobby here, and my sense has always been that haggling isn't the way to go. Even if you "win" the negotiation, you're going to get treated differently by the provider because you haggled--that's just human nature. This isn't a yard sale item where we quickly part ways. You're going to spend an hour or more with this woman hoping for as intimate of an encounter as possible. If you don't like the price, don't book the lady. Either the market will correct and her rates will come down, or her services will demand higher prices, causing you to rethink your tastes or your budget.
I'm just writing this for those of you that may have been on the fence about Rene, saw this thread, but aren't necessarily concerned with providing a deposit. The response to his comment: "I can only imagine if I had agreed to the deposit" is: you would have had a great time, in my opinion. Stay safe, lads and lassies!