Last week's survey on EMV at restaurants yielded results from 27 payment providers that service restaurant merchants. Together, the respondents service over 170,000 restaurants.
"The card brands support tip add on for EMV cards in the same way that they do now with non EMV transactions. The authorization amount and the settlement amount (with tip added) can differ and will not be declined as long as all the other restaurant merchant processing rules are followed," according to the EMV Migration Forum and TSG.
As the statement above and the survey results show, tip add-on at restaurants with EMV is allowed by rule but sometimes constrained by technology. The sheer number of players in the payments value-chain makes EMV (and other ecosystem changes) very complicated in some scenarios, and as such, not often black and white, but gray.