We don't know for a fact that this person was a scammer because the scam did not actually carry out. But there is a good reason to suspect that the person was indeed a scammer. First of all, the situation is a very common one with scammers. And the fact the person fled right away after being called out on it? Why would she need to disappear if she felt she was doing something ok? Now people can dissect that all they want, but most people wouldn't disappear, they probably would just end the trade annoyed that someone accused them of something. Although this person must be new to scamming to only put up NPC pins and think she'd get rare for it.
I don't think there's anything wrong with contacting VMK about it...in fact I would encourage ANY player to contact VMK if they strongly suspect someone is a scammer. I would be careful of the wording and not imply that you were scammed if you actually weren't. But providing VMK with a report and telling them the situation along with letting them know that the tactics are very common for scammers will give them a heads up on that player. And perhaps they can look into "back logs" or whatever to see that player's history or maybe keep tabs on that player in the future (especially if future reports come in). I've done that with players who've attempted to scam me.