How to not approach a woman (creepy story inside)!

I (29M) was having a nice walk in the park to enjoy nature with my gf (30F) of almost 1 year. I was in need of a bathroom so as we headed there. We were holding hands as we were walking on the path there. Turns out I took longer than expected in the bathroom (no details needed lol).

When I finished my business, I came outside and as I walking to my gf I could notice her body language was off, so I asked her if she’s ok. She told me a guy approached her and tried to ask for her details.

The bad –

Now let me explain further (when it is not ok). She was at a public sink washing her hands and took off facemask, then a guy appeared behind her (in the mirror) then started talking to her – should never approach someone from behind in such a creepy manner.
The convo lasted about 30 secs she told me he approached with his phone open, asked her name (she didn’t give) then asked her to put her details in his phone. After she rejected him he walked away.

The ugly –

As we were walking to the toilet (While holding hands and clearly an item) this guy walked right past us in the opposite direction. My gf told me she saw him from a distance and then he was looking at her the whole time (I didn’t notice). She said he walked right next to us and past us, she told me he was looking at her a lot as he passed (I think I was in middle of talking during this so didn’t notice).
Now imagine that, this guy saw her and me, then he must’ve looked at us from behind and watched as I went to the bathroom – then he approached her in a quick manner, then fled the scene.

I asked my gf about his appearance or to point him if she saw him but we didn’t see him again.

Note: I’m in Thailand and my gf is Thai, this was especially strange for her as she said it never happened before (guy was American sounding she said), and immediately she knew it was the guy who past us – she told me she was scared and asked him if he needs help for directions or something. Then mentioned her bf is in toilet then he left.

Tldr: If you see a couple together, do not try approach the woman while the guy goes away to the bathroom or something. Have some ethics and respect your fellow man and women🤝