Can We Use Dragnet Tagline?

Dear Rich: I would like to reprint the line, "All we want are the facts, ma’am." I cannot confirm if this is in the public domain/fair use. Any information that you can provide is appreciated. If you do not know the answer can you refer me to someone who can help? We wish we could refer you to someone, but alas, we don't know of anyone else providing free legal information about Dragnet dialogue. So, here goes:

• Under copyright law, you're okay to reprint the line. It's too short by itself to be protected. (We've written an article on the subject, as well.) 
• Under trademark law, you should be okay (except for using it on entertainment services and related merchandise). No one has registered the phrase, although there have been registrations for the more well-known but never-uttered-on-Dragnet line, "Just the Facts" (made popular by a Dragnet parody.) Oddly enough, the "officially licensed" merchandise uses "Just the Facts" (Go figure!) In any case, avoid using it for entertainment services or you may hear from Jack Webb's estate. BTW, if you plan on using the phrase to sell products or services, it's always wise to search USPTO records, first.
• For right of publicity reasons, we would advise against any attempts at commercially exploiting the phrase in connection with Jack Webb's image or personna. If the estate learns of the use, they'll likely come after you.