Colorado's "Respect Life" tag is intended to memorialise the Columbine High School massacre on April 20, 1999, however when originally proposed, it was criticised due to its somewhat controversial anti-abortion slogan. Nevertheless, it was issued and is now very popular. At bottom is a blown-up version of the central logo.
UPDATE: (January 25, 2003) Today I saw a Chevrolet Blazer in Arvada, Colorado, with Respect Life plates with the slogan covered up intentionally with electrical tape. Evidently, the slogan is still a problem for some who want to memorialise the massacre yet don't want to meddle in the controversy of the supposedly anti-abortion slogan.