I'm just trying out the new comport object in trunk, and it seems that it no longer outputs an error when you try to send bytes to a closed serial port, even with [verbose 1(. While the earlier messages were less than ideal, I think there should be some kind of notification if you send bytes to a closed serial port.
It might even be worth making it a pd_error() so you can easily find which object has the problem, but I am not sure.
.hc
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kill your television