It's no wonder Universal is pushing hard for the return of racy "red band" trailers for R-rated movies: On April 13, the studio opens "Forgetting Sarah Marshall," the latest raunchy comedy from the Judd Apatow factory. (He's the pic's producer.)

While some argue against giving away too much of the movie in a trailer, what better way to advertise "Marshall" than to tantalize auds with some of the actual sex scenes?

Sony, too, has been lobbying theater owners to allow more tantalizing promos, instead of the benign "green band" trailers that are approved by the ratings board for all auds.

And no surprise: Sony and U are the biggest traders in the recent rush of R-rated comedies.

Skittish theaters owners stopped playing red-band trailers years ago: Accidentally running a red-band trailer in front of a PG-13, PG or G film sometimes stirred patrons' ire and watchdog scrutiny. With red-brand trailers, the content in the trailer itself is rated R by the ratings board.

But with the evolution of technology and the transition to digital screens, studios and exhibs now have more control in preventing such mishaps. Hence Regal Entertainment's recent decision to again allow red-band trailers -- on a case-by-case basis.

The move is significant since Regal is the largest U.S. circuit, controlling some 6,388 of the country's 37,000 screens. Insiders say other theater chains could follow Regal's lead.

Regal's decision arose as something of a compromise. Some studios had been lobbying exhibs for a new category of trailer that falls somewhere between green and red. Theaters owners, though, didn't go for the idea of a "yellow band" trailer.

Better to stick with blaring red, it seems.