Regarding forwarding: that step is already being taken away - it's in beta for a number of our customers, and we'll be adjusting workflow then releasing to everyone.
There's lots of people who don't have access to their DNS records but still want a tool like this. We want this utility to be simple for more them, too!
As far as SHA1/MD5 encryption - we know better than to use weak encryption on any TRULY sensitive information. In the context of the walkthrough, we're talking about internal IDs and other things that you might want to be obvious to your customers, not things that pose a security risk to you or them. If you even thought about using something like that as part of a unique identifier in your email replies - I think there would be bigger problems at hand than choosing SHA1 or MD5 to obfuscate that information. :)