319's with no marker lights , or reds on the front coming out of the non-track circuited turnback at SAC was not that uncommon - reported several , often informally by catching the drivers eye and pointing with one hand at the front end , and at your eyes with the other. They got the message. Once with a "thanks mate" over the PA when moving off , after the mandatory running brake test, - or a soft horn tone.
The best I ever got was a “Sh*t thanks guv’ “