Comment by jffry

I wouldn't read anything into the presence of tracking pixels. They plausibly would route all outbound mail through some system which instruments it with click tracking and tracking pixels, and probably also handles rate limiting, bounced delivery, unsubscribe, etc.

At least, I'd consider doing something like that if my systems sent a lot of email and had to deal with a myriad of tracking and compliance needs.

Plus if you're going to send an "accidental" email that gets everybody talking, you would absolutely want to use something a little less dry and clinical, because that'd get a lot more coverage outside of the usual tech circles.