Last time I volunteered but not get bumped.. when I go to the plane (the last-5 person) with a backpack and a plastic bag of gifts (no checked luggage, legal to have two).
The FA saw me and asked where is my seat, i said 17B (exit row) show up my BP. He galdly said there is some place at the back, help me unload the pack and place it, find another spot for my plastic bag... nice touch.
I think the following may be factors:
1.I hold up and showed him my BP with <b>large marker word "vol"</b> which means I am a volunteer so boarded last.
2. this domestic leg is "rerouted" in "Y" Class, so my ticket (or the manifest) will show I am "Premium", "Adv Gold", and "Exit".
3. I kindly help people in front of me to get to his right seat.
....I think I will always show the FA that large "VOL" mark on my BP.