My experience as both a renter and an owner is if the unit is what's needed and the price is right, the unit gets rented. I contact a lot of owners who only accept checks and they get their units rented just fine without me renting from them. 98% of everyone who inquires to rent from me is willing to pay by credit card either over the phone or via Paypal. 1% wants to use escrow but to date none of those people want to incur the cost of the escrow and thus they don't rent from me. It has oddly been my experience the people who want to use escrow are also more difficult to work with and I'm actually relieved they don't book thru me. I don't mean any insult to you Polinac, there are always exceptions to the rule. 1% fit into an exception such as the customer is another vendor, I know them personally, the reservation is so far in the future (6-12 months) and I have a good vibe that I agree to accept a check.
Just as there are many renters who do not think they should bear the cost of half or any of the escrow, there are owners who will not agree to a payment method which costs them money. There are also a lot of owners who only accept checks because they are only familiar with checks. I suspect some owners will not use escrow because they believe the escrow companies are like up front fee sales companies - scams.
Personally I feel it comes to this: Owners are the sales agent. As such they are the ones to choose the payment method they will accept. If you can't convince them to accept an alternate option that is your problem, not theirs. When an owner or seller has terms I don't like, I choose to not do any business with them. I recommend you take this option. Maybe if enough customers refuse payment methods owners require, owners will accept a wider option of payment methods.
That's too bad about the people who didn't have any reservations because the owners cancelled them. You have valid reasons to be careful or a low percentage of unscrupulous owners just as owners must be careful of questionable renters. If an owner won't change their payment terms though, are you willing to pay more for your vacation to book with an owner who will? If you think about it, making this decision is a form on insurance. If you want to be safer, insurance costs money. So far few of my customers have been willing to pay for that "insurance".
Beck