To do a crawl across a meaningful percentage of the Internet and refresh this every 24 hours is hard enough even if you only capture the front page. Very few sites include stripe.js in the source on the front page. So you would need to crawl deep enough into a site to hit the checkout page and capture stripe.js in the head section which is exponentially more difficult.
Indexing your crawl and passing this off to a team to extract contact details and send it to a client so they can reach out all within 40 minutes I would say is nearly impossible. It is possible they already had his details but I cannot see anything on his site that would trigger a "likely to switch payment gateways" alert.
My guess is this was completely random. A good sales rep will make 60-100 outbound calls per day along with a bunch of emails. Multiply this by the number of outbound sales reps in the payments market and you have a lot of sales activity.
My guess is that the company that contacted you is using one of these (Stripe requires your public key in the head of your site and linking to their JS). BuiltWith is one such service: http://builtwith.com ... NerdyData & Datanyze also: http://nerdydata.com, http://www.datanyze.com
Subscribers use these tools to find people who are trying out competing services (they are not cheap, BTW). Often, if a site only recently added JS code–for example, say, KissMetrics–you can assume they are still in the trial period. That gives you a window of time to try and sell them on your competing product. Or, if you sell a special WordPress plugin, you can use these services to find WordPress sites.
Stripe doesn't have a trial period per se, but its pretty easy to switch between the modern payment providers and if it was only recently installed, its safe to assume you don't have a lot of customers yet.