I booked a room on Priceline for the Ren in DC. BTW I Bid $71

I have had issues in the past with Marriott's placing a hold on my credit and/or debit card for incidentals, which usually means the total cost of your stay plus $40 per night for incidentals. The problem I have is that I have already paid Priceline so Marriott already has been paid. Worrying about me running off without paying isn't an issue. I always have pay per view disabled, and a note on my account to disallow room service and phone calls.

Yet when you check in they ask for a credit or debit card and the card machine is set up to automatically charge you and it ties up funds up to 14 days! I had the Kansas City Marriott ACCIDENTALLY withhold $2500 instead of $250 for 14 days and they couldn't reverse it and I ended up stranded in KC for a day until my bank could transfer funds to me! This is why I am paranoid.

At no point have I ever signed or agreed to allowing the funds to be withheld and I would like to know the following:

Can I authorize them to withhold an incidental amount? ($40/night)
Can I refuse to have anything withheld?
Do Marriott employees realize prepaid rooms are paid for?
Does anyone have any experience bypassing this ridiculous practice?

Thanks in advance!