Robsten Together in London Again—So Where Are the Pics?

How are Rob and Kristen spending so much time under the radar?

Kristen Stewart and Robert Pattinson continue to romp around London together—totally undetected. Which begs Robsten believers and non-believers alike to ask: How is that possible?

There have been more sightings across the pond of Robsten than the friggin' Loch Ness Monster.

And there was a supposed make-out sesh at pub Marquis of Granby on Tuesday, and last night R & K hit up the Halfmoon in London together (which a rep for the venue confirms) to watch Rob's sister, Lizzy Pattinson, perform.

So are Rob and Kristen just that good at being sneaky?

"The paparazzi are way more respectful here in London," 'fesses a fancy AT London source, who is no stranger herself to the pap flashes in Britain. "It's actually not even comparable to the states."

Adds our royally dusted socialite insider:

"I think after Princess Diana's death, a lot thankfully changed. There were more regulations put in place."

OK, then, what about camera phones?

Those against the Rob-Kristen dating rumors claim a fan or onlooker would be able to snap a few pics if they really were together all the time, 'tho there have been some.

Take Lindsay Lohan as an example (we know, we know). She's one of Hollywood's biggest train wrecks, and everyone nosey-knows whenever she's out, she's totally living up to her Blind Vice name. That's never debatable, yet she manages to sneak out of clubs and after-parties with her habits undetected.

Let's face it. Some people are just respectful of celebrities, despite how much a picture of them may be worth.

So, let's hope Rob and Kristen keep enjoying their time over in London semi-privately, but the clock's a tickin'. Rob will be back in New York City by Saturday morning for the Remember Me junket.

Think Ms. Stewart will be making a pit stop in NYC before heading back to LA in time for the Oscars? We say doubtful.