I have seen much less subtle. Coupla dealers outside their tent by ours at Glasto C2000 singing loudly renditions of
"GET YOUR GEAR OVER HERE"
"DONT BE SILLY BUY SOME BILLY"
"IF YOU NEED WE GOT WEED"
"BREAKFAST TODAY - SPECIAL K"
"IF YOU PLEASE WE GOT E's"
Went on all fricking weekend