The jQuery CDN is also a semi-frequent victim of Sky's filter. I pause here simply to note that it's quite possible to use the infrastructure's distinctive beh

The jQuery CDN is also a semi-frequent victim of Sky's filter. I pause here simply to note that it's quite possible to use the infrastructure's distinctive behaviour as an oracle to scry a complete list of all blocked sites, and to monitor that over time, given just a few volunteers on each major ISP.