I have noticed a few stations who are accidently leaving their mic open. This can easily happen if you leave the Mode switch at VOX. I leave my mode switch at QRT when I am not planning to transmit, so i can never accidently key on the mic. As with any transceiver, never leave the VOX on.
There is some advice about using the Mode switch and Push-To-Talk at the FAQ page http://www.qsonet.com/qbb/viewtopic.php?t=13