The alternative would be to not include "RE:" in the subject, which makes it looks like a reply to an earlier thread. The subject is subject enough already. Don't manipulate it with a "RE:" to imply something more.

That said, I've been working with Twilio on and off for 2 years and have never received an email like this from them.

Looks like this is a bit of email usability fail on our part. When you first sign up for Twilio, you receive an email with the subject line "Welcome to Twilio... Learn to Build Your First Phone App in Less than 5 Minutes" and then 7 days later we send you an email introducing our CEO that says "RE: Welcome to Twilio..." in the subject line. The goal was that these would get threaded together, but they don't since the from is "Twilio" in the first and we use real names in the other emails (the one from Jeff says his name, the one from me says my name, etc.)

Sorry about that, it's an easy fix to remove the RE:

Thanks for addressing that.

Fair enough. The use of Re: is def a bit manipulative/not truly representative.

Interesting, maybe it's something they rolled out more recently for their newer members. I only started with them a couple months ago.

The alternative is that they don't lie about their content.

Personalization of this type is pretty common in marketing communications of all types (direct mail, emails, etc). Calling it a lie seems a stretch.