My strange beach story

Was reading the creepy thread and had the idea that maybe I could get some ideas what was going on when the following happened. Not exactly creepy but just something that I've always wondered what the hell just happened there. So...
Was on Carcavelos beach near Lisbon about 8 years ago with my girlfriend. Was late in year so beach was empty but it was a beautiful day so we went for a dip and then lay out on beach to take in the sun. Soon after a pretty girl on her own lay out fairly close to us in her bikini to sunbathe. Not long after, two stunning girls, and I'm guessing they were Swedish, both were blond and nicely tanned, came within ten feet of us, and threw out their towels and bags etc and began sunbathing too. I didn't think anything of it, it was a nice spot on beach and I just thought that people like to stay in a group rather than staying on their own. They then proceeded to go topless, but did it fairly discreetly, But not so much that I didn't get a nice view(I was wearing shades!). After yet another while I noticed this guy walking along the waters edge in front of where we were. He looked local, was fully dressed and was talking on his phone pacing back and forth as if it was an important call(if it was today Id say perv with a camera but I hadnt even heard of camera phones back then Id say) I dozed off or just didn't notice him moving away. Next thing I remember happening is one of the topless girls putting back on her top and going for a swim. While she was in the water, the guy nonchalantly walks up to her friend and says something to her, kneeling down beside her. I could tell she was uncomfortable and she covered up with a towel. Guy soon walks off but as soon as the girl who was in the water came back to beach, her friend obviously tells her about the guy, looks a bit shocked/pissed off and both pack up their stuff and leave the beach.
In the meantime the guy has moved on to the girl who was on her own on the beach. He knelt down beside her and started chatting. I remember she had to take out earphones. I was thinking to myself not a chance creep move on but to my amazement she started laughing and chatting back. She was English as I heard her accent. Next thing she's having a cigarette with this guy and then to our amazement she packs up her stuff, gets dressed and walks off with this guy off of the beach. To this day all I'd love to have known is what he said to these girls and why did the single girl leave with him. So any guesses as to what was going on that day? Ps sorry bout the long post, fair dues if your still with me!