The following prevent you from inviting player, and from sending trade invitation, when you only want to scan him.
Use the two keys right to the print-screen button.
Set Group invite to 'Roll', and trade invite to 'Pause/Break'
So you never invite someone for group or trade by an error. Also it prevent from that accidents, when you think you have chat and type, but the chat window isnt open.
It happend to me a few times, mostly ending up with 2 invited people, if 'T' was used in chat also...
Another reason why i posted this, is that get ~1-2 group- and/or trade invites on my weapon dealer, accidentically. I ignore them mostly when first happend, normally followed with a green msg: "//sry wrong comms" or so.
Combine it with [Shift] or [Control] is a good idea too. Same result.