I have totally relearned my way of typing in game to avoid issues with this stuff.
I always type every command for MQ2 in the MQ2 chat window.
Any time i use say or group or guild or fs or whatever, i always always type /g, /say, /gu etc in front. No default channels ever.
I always always watch the MQ2 window when typing a command like /mac or /melee. There's that stupid bloody delay in the cursor going to the MQ2 window when you use the '.' button and so if i didnt watch it, half the time i'm missing the first letter. Most common one is .tar... usually ends up being /ar.
My best was in blackburrow when it was first revamped and i was looking at the map and choosing my targets and i accidentally warped onto a named that i had targetted.. and a group was sitting right there infront of it. One of the guys sent me a tell saying "Lol, nice one". Fortunately he must have been a hacker cause he didnt call me out for it. Then later that night i accidentally used /warp s while dragging a corpse. Someone noticed that too.
Pretty good to only make a few mistakes in 5 years of using MQ, but that night was brutal.