You don't want to do a BTCpay right before the order match is set to expire (especially in the future, when blocks are closer to being full).
Can this be foolproofed somehow before going mainstream? I'd hate to think of all the posts on the forums when people start losing BTC. Maybe the BTCpay operation can accept an order match number as an optional parameter and the escrow time extended if necessary for the amount of that specific order only, provided BTCpay is called before the offer expires. The number of blocks to extend would be based on what the protocol determines is reasonable at the time or could be hardcoded initially.
This will come with the GUI/online client. Btcpay right now is not at all user friendly, (neither is order matching), but remember this is
alpha quality software. Bitcoin wasn't built in a day (or for that matter, a year).
I encourage people to sign up for reddit (if you haven't already) and try to answer outstanding questions in the reddit thread:
http://www.reddit.com/r/Bitcoin/comments/1wtz2b/2124_btc_destroyed_in_proofofburn/A lot of people are sold on the idea (unlike, for instance, NXT); they just want to know how to acquire some XCP.
Everyone, please help spread the word. To be successful as an asset trading and betting platform for financial instruments, we need broad community participation not just few early adopters.