It’s not done well and I wish BTC Sell remained (if only after enabling it in some Settings > Advanced menu), but the majority decided to cater to the lowest common denominator.
So the order can match only if someone first created a BTC buy order (ex: sell XCP for BTC).
I think (but I don’t have time to verify that) that you can’t denominate sales in BTC in CW (but you can via the API or CLI).
Okay, I just checked: you can’t sell for BTC in CW.
As you can see as soon as one clicks Other and tries to enter BTC…, CW autocompletes the field with other CP assets, but doesn’t allow you to set BTC.
She’d have to use the API or CLI.
If the offers match, then Bob would have X blocks (I think 20, but you can see in CW Support FAQs) to send BTC in (say, using counterparty-client). If he doesn’t, then the match is cancelled and Alice’s offer is returned to the pool of offers that can be matched (as long as it hasn’t yet expired, i.e. when they were matched the offer wasn’t more than 980 blocks old; 1,000 being the default offer duration).
So Bob can only screw up Alice by constantly making matching troll orders, but don’t forget that he loses money (1%, IIRC) every time he fails to make BTC Pay (details are explained in the FAQs).
Someone could revert the patch and run a custom version of Counterwallet that allows BTC Sell.
But how do you get paid for that (estimated ~$1K/year in expenses)?
