Kate Beckinsale -- Sheriff's Deputies Got Her Back and Front After Dinner

Kate Beckinsale and Sarah Silverman needed some serious protection ... for the 10-foot walk from a restaurant to their cars last night -- at least someone thought so, since for some reason cops escorted them.

Two L.A. County Sheriff's deputies walked Kate ... and then Sarah ... to their vehicles outside Craig's in West Hollywood -- and there doesn't appear to be any major threat to their safety in the video.

There are about 10 paparazzi there, but that's status quo at a hotspot like Craig's.

The Sheriff's Dept. tells us it has no official record of a call for help from the restaurant ... so, it's a mystery why the deputies were there.

Fun fact: Jerry Ferrara got NO escort, but check out the clip -- he seems to be just fine when he gets to his car.

A similar scene played out last month when Sean Penn was walking out of Craig's -- but he got THREE deputies.