Actually, many of the girls do have SOs. And always remember this simple fact: "if she's doing something with you, she is doing it with others". If you do meet a girl outside, keep this fact firmly in your brain. Personally, I would listen to Jeg.
I once met a girl outside for "take out". In the end, it cost me a ton of money and wasn't worth it in the end. When she moved spas to one that I frequented, I was tempted to see her again, but could never shake the feeling that I had conned myself. In short, it ruined the whole experience for me and I never saw her in or out of the spa ever again. I remember picking her up at her house, and I remember seeing her FB pics. Yes, she definitely had a SO!