- Honk if You Like Cheeses,
- Honk if You Would Like to See My Finger,
- Honk if You're Going to Run Me Over,
- Honk if you Like Prune Tacos (our favorite),
- Honk if You Like Peace and Quiet,
- Honk if You Are Living a Life of Quiet Desperation, or
- Honk if You've Never Seen a Gun Fired From a Moving Vehicle (scary).
Honk If You Receive an Objection from A Trademark Examiner. Upon receiving an application for a slogan, the trademark examiner will probably object on the basis of § 1202.03 or § 1202.04 of Trademark Manual of Examining Procedure or TMEP (excerpted below).
§1202.03 Refusal on Basis of Ornamentation Subject matter that is merely a decorative feature does not identify and distinguish the applicant’s goods and, thus, does not function as a trademark. A decorative feature may include words, designs, slogans, or trade dress. This matter should be refused registration because it is merely ornamentation and, therefore, does not function as a trademark ...It's on these basis, for example, that the slogan THINK GREEN was rejected as a trademark because it was merely a statement of environmental awareness. The slogan, HAIR COLOR SO NATURAL ONLY HER HAIRDRESSER KNOWS FOR SURE was registered because consumers associated the slogan with a particular product. The only way to overcome this objection is to show that consumers associate the slogan with your products or services.
§1202.04 Informational Matter Slogans and other terms that are considered to be merely informational in nature, or to be common laudatory phrases or statements that would ordinarily be used in business or in the particular trade or industry, are not registrable ...
Honk if You've Used the Wrong Classification Codes ... Also, you referenced code 045 in your question. Class 045 is for legal services (Honk If You Like Litigation) so we don't assume that's what you meant unless you've come up with a slogan for a law firm (Honk If You Like to Pay For Overpriced Associates).
Honk if You've Tried Copyright Protection. Finally, a bumper sticker slogan cannot be protected under copyright law as copyright does not protect short phrases. A short phrase can be protected in conjunction with an illustration or it may be protected in some cases, if it is taken from a larger well-known work, such as taking a line from a movie.