I don't think opening a channel without tapping a commbadge is particularly bad directing - the commbadges record constantly (remember Admiral Ross & Dr Bashir taking off their commbadges to have a private conversation in Inter Arma Enim Silent Leges?), so if Cmr. Ryker says "Ryker to...", then the commbadge will automatically open a channel to the person identified if possible. Tapping it might be good form, but not essential.
Answering... more of a glitch, since just because someone calls you doesn't mean you don't want to answer, but the commbadge may base on the tone of voice used (since people tend to speak a different way on the phone than they do in person). Or maybe it DOES automatically open, and you have to say "Close Channel" if you don't want to answer.
Answering... more of a glitch, since just because someone calls you doesn't mean you don't want to answer, but the commbadge may base on the tone of voice used (since people tend to speak a different way on the phone than they do in person). Or maybe it DOES automatically open, and you have to say "Close Channel" if you don't want to answer.