Comparing the current account with the drain's missed a switch to another
account and back before an answer arrived: a refusal given to the other
account then failed the capture. The account listener now counts every
change, and a drain stops at the first one.

Leaving a capture for its account also dropped the note that a write sent
for it may have landed, so discarding it gave no warning. It is kept now.

The fake cloud answers as the server does: someone else's strategy is
forbidden, and a create under a taken id is a conflict.