Fight fraud frugally
blog.siftscience.com
blog.siftscience.com
Yes, developers should be smarter about escaping and using string values, but this seems like a very easy thing to get wrong.
Machine learning based anti-fraud systems perform asymptotically better as you get more variety and volume of data, and Sift can market it as such ("our network consists of over X merchants"). The 100 dollars of free service they are giving away is likely worth more to them in the data alone. The biggest credit card fraud solution I know of markets itself as a better solution because of its "consortium" of thousands of card issuers: http://brblog.typepad.com/files/falcon_scoring_srvr_2519ms.p...
This arrangement also lets Sift very naturally eases merchants into being paying customers as they grow.
[1] http://www.forbes.com/sites/roberthof/2013/06/05/amazons-ad-...
... and is that pageview information predictive, so far?
EDIT: I just checked out what you mean, since Sift utilizes Javascript code for their api call to determine risk, I agree with you...it would render their pattern check ineffective for the Javascript api integration...they need to run server side code, which Sift offers in their REST API.
Sift Science also has both Javascript and server side APIs. See https://siftscience.com/docs/rest-api for info on the REST API. This allows companies to send all relevant transaction and behavioral data to Sift even for users who don't execute Javascript.
Assuming you're putting all of the relevant data into Google Analytics, how would you query GA with a pending transaction and figure out the probability that it is fraudulent? This is the sort of thing very few (or no) general analytics products do, but is the domain of fraud prediction software.