Did you check your server logs for crawlers on the 16th to see who all visited? That may help you narrow the field of possibilities. I was also under the impression that PositionTech had their own crawler. Also, for what its worth...I've used their service and found it to be quite useful.
>I'm taking that statement as a recommendation for PositionTech?
Is there another company who's been able to get deals with many major search engines (competitors), and turn around and walk the line with seo's, and the general public? They are always on the hotseat.