Personally, I think I'd be cooperative but in a sly way.
Tell them you'd be happy to sell them the vinyl they need (to help them out).
When they screw up the job they'll be back and maybe this time they will ask you to cut it. Do so, but don't weed/tape (unless they specifically ask).
And do everything with a smile and say "always glad to help out" while taking their $$$.
Eventually you'll probably get the entire job.
+2
AND... ROFL @ BSnyder!!!!
We get this quite a bit... I tell them we're a franchise and buy from our franchise commissary LOL
Had a call yesterday...
customer: Do you sell those cheap plastic signs you stick in the ground?
me: *heavy sigh cuz I know what's comin* Sure we do!
customer: As cheap as those guys with all the little signs around town at the traffic lights?
me: NOPE!
customer: How come?
me: Because we don't sell cheap signs, only high quality products.
customer: So, I don't suppose you can give me the number for one of those other guys.
me: Why don't you get it off one of the millions of signs by the road?
customer: I'm not out and there aren't any around here... thanks for your time.
I just hafta laugh... I don't want those kinds of customers anyway!