I've seen shops send in "plants" that would dramatically show this lesson. Send a plant customer in go through an upsell or repair process and then hav them refuse to pay because of the lack of signature (if your state has such strict regulations).
Most dealerships I know that catch this do so at the dispatch window and place a spiff/penalty on it both ways. They'd spiff the dispatcher say a buck for every ro they found without a signature and subtract a buck from the service advisor's bonus or other commissions.
One shop I worked at also mad signs on the drive that said in bold type facing the customer, "did you get a copy of your signed estimate before you leave?" This provides the customers to remind the advisors that they want their estimate copy which was a cue to get the ro signed.
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** Rob, Editor WD&S **Help is only a message post away!
robc@dealersedge.com