Germans and Vietnamese: touching women they just met?

I have a friend who is studying abroad in Teubingen. The first day she's there, this Vietnamese guy who claims he's been in Germany for 8 years lets her use his internet (they don't have wifi in those dorms and her internet isn't set up yet) then asks her if she wants to go to the bar.

He doesn't speak English and she wants to practice her German.

She says yes, being underage in the US but not in Germany, and not wanting to pass up going to a bar. On the walk over there, he keeps putting his arm around her waist. She just steps further to the side away from him as they walk to the bar, but every once in a while he tries it again.

Then at the bar he pays for her drink faster than she can refuse. She wants to tell him she has a boyfriend then ditch him, but doesn't know the way back to the dorm building. Then on the way back, he puts his arm around her waist again as they walk, and again, she steps to the side away from him as they walk. When they get back to their building, they take the elevator up to the floor they both live on.

When the elevator door opens, she tells him that she has a boyfriend and quickly leaves the elevator and goes to her dorm room.

That was a few weeks ago.

Today, he invited her to hang out with him tomorrow and practice her German. She suggests 7PM and initially he says yes, then says no because he has a Judo class at that time, then asks her to meet him at 10PM. Being naive and not very assertive, she says yes. They agree to meet in the common kitchen of their dorm floor.

Um... should she worry about this dude?

I don't think Germans or Vietnamese are very "physical contact with strangers they just met" type cultures, so... do you think this guy is up to no good?

Or is there a cultural explanation for this?

What's going on?

Is there a reason to worry?