I've had to. I help my friend at her Artist Alley table, so at the beginning and end of each con we have to lug a bunch of stuff from her car/the hotel room to the table. This year we had something like one trunk the size of a bathtub, two suitcases, a bunch of PVC pipes and other structural materials, etc. I'd also taken off parts of my costume (gloves, so I could have a better grip on what I was carrying). We were also running late. So it was a bad time, in multiple ways.
I got asked for a lot of pictures while carrying stuff over, so I just apologized profusely and let them know what table we'd be at. Since everyone comes by the AA anyways, it worked out.