[Closed] Online dating advice needed... This is pure car crash! Bear with me!

So, a long story cut short. Had a mixed success with online dating since I split from my ex in April, had met someone who I thought was the new GF, turns out she was just using me (albeit just sexually, thankfully not financially or anything) before I ceased to be useful and got rid ASAP. Anyway...

Been chatting to a few more through tinder/pof as you may expect, though I'm terrible at getting back to them as I'm always so busy with work. Still at least I'm not coming across too keen eh! So, this evening whilst in the pub with a couple of mates, managed to secure myself a couple of dates over the next few days with a couple of girls I've been chatting to. Woohoo, go me! So... Told my mates "I've got a date tonight" when I came back from the bog. They were both asking "come on, let's see a pic" the moment I said do... You can see where this is going right?

Turns out, the girl I've agreed to go on a date with tomorrow is the rather brief ex GF of my mate that I didn't meet 9 months ago, when he was seeing her. Why didn't we meet? Well to be fair, I don't think he was proud of the relationship to say the least! He admits he was a sap, but she got under his skin, stole money off him, continually abused drugs (class B's if not A's apparently!) on the side, is a complete alcoholic, and at the age of 35 has had to move back in with her parents to stop her from going completely off the rails!

This in mind, it explains a couple of oddities in her behaviour since we've been messaging online. So, not that I wouldn't anyway, but I totally respect my mate's standpoint, and have heeded his warnings. I have asked if he wants me to go along anyway, then make her feel totally awkward by name dropping him or anything, and he says no. But by the same token he says go along if I want, and see what she's really like.

So... I'm supposed to be meeting said psycho (oh yeah, she hit him and threatened him with a knife apparently!) tomorrow night. The friend in me thinks that I should just not show up and just disappear off the radar. The social voyeur in me is keen to turn up, and see what she has to say for herself knowing just how much of a nightmare she is (oh yeah, she cheated on him several times in just 3 months too)... I was supposed to meet her on Saturday night just gone, but she cancelled with only an hour to go, I'm guessing she had a better offer! My friend warned "watch out, she'll try to find out where you live ASAP, and you won't be able to get rid of her soon after" which rings true, as 2 weeks ago she briefly said about "how about I come round yours" for a first date to which I replied cautiously "how about we meet somewhere mutual first?" after which she went quiet for a week...

So what to do? Clearly I don't see anything going anywhere. But the voyeur in me is keen to see just how bad an individual can be, but I already know, and can pick out the tell tale signs. By the same token, part of me (and my mate) thinks what's the point in wasting 2 hours of my life meeting with her. He understand where I'm coming from, and knows I won't make the same mistake he did, and I understand and respect his view point. I did suggest he should accidentally be in the same pub on the same night, sat in the next booth, accidentally overhearing everything but he seems that emotionally damaged by her that he wasn't keen! So is it my duty, given the situation, to get her back on his behalf? Or should I really just not waste my time and delete her number and forget she exists, even if I was only interested in the comedy factor anyway?

So, hive mind, what's the consensus? Honestly, all suggestions considered, at the end of the day she doesn't know where I live and she's done a number on my mate after all!