I get myself on the VDB list when checking in at the counter. This is one reason why I really detest the check-in machines. I always try to get a human being to check me in or at least look at my PNR.

My standard question to the counter agent is, "Is this flight heavily booked?" If anything close to yes to this question then I state, "I may have some flexibility today. I may be able to take a later flight if you need volunteers." At this point, I have established myself as a good guy, trying to help CO in a tough situation. If I get put on the list, fine. Over the years I've had all kinds of good things happen by volunteering.

If I have luggage, and if it's at all possible, I try to have my luggage tagged as being possibly a VDB when I check in. Some stations are better than others at this. Having checked luggage can sometimes get you bypassed as a volunteer.

I repeat my questions at the gate, if possible with the lead agent. I'm trying to establish who I am. I often point out where I'll be sitting if they need me.