Couldn't you just set the seats in a kind of locked state as soon as the transaction arrives ( 0 confirmations) and transfer the seats as soon as it's confirmed?
This is a good idea. But the locked state needs some time limit. Maybe 24 hours?
The answer is that block 152218 followed block 152217 after a delay of 1 hour 39 minutes 7 seconds. This was the longest inter-block interval in 2011.
How about: 6 x 1 h 39 min ~= 12 hours?
This is not about long block times. The issue today was because the transaction was sent but it was not picked up by a miner until 13 blocks later. Maybe the tx fee was too small?
This is about how long we wait for transactions to be picked up. If the tx fee is too small maybe it is never picked up. But we do not want to lock seats forever. We need some time limit. If it is picked up after the limit then it becomes a donation to nastyfans or refunded to buyer minus 0.0005 BTC.
After sitting on my brain for a day I recommend:
1. The buyer must submit a transaction within 7 blocks. (This clarifies existing policy.)
2. The transaction must become part of the main chain within 1000 blocks. (This is new policy.)
3. The transaction is valid after 6 confirmations. (This is already policy.)
4. If a transaction is submitted within 7 blocks but does not become part of the main chain within 1000 blocks the purchase order is canceled. If the transaction becomes part of the main chain after the purchase order cancellation then nastyfans will refund the amount (minus 0.0005 BTC tx fee) to the buyer if the buyer accepts donations. Otherwise it becomes a nastyfans donation. (This is new policy.)
If there are no good objections I will start a poll for these policy additions.