What an interesting thread!
"Scene Tape"
The Blue tape that you have seen, is most likely 3M water resistant masking tape, applied 3 or 4 layers thick, will provide excellent protection against "Road rash", one of the benefits of using this tape is its a "Low tack" tape, meaning that its unlikely to pull fresh paint off, which could be quite embarrassing having just arrived at a show...
I use it to gauge what time a show is going to end! ie, the blue tape gets broken out about 45mins before the end of a show, leaving at this point is normally good practice, to avoid getting stuck in the traffic
Me, I just get my foot down on the way home! sod the stone chips..
Thom