@slh While the enormous amount of academia pouring from your fingers is impressive, I'd argue pretty heavily that the time you invested would have been infinitely better spent updating this:
and this:
to simply, plainly say "IMPORTANT - if your ISP requires a specific MAC address for your WAN connection, you will need to take the following manual steps post-upgrade to restore functionality..." and lay out what they are, versus more or less mansplaining how "well, a lot of other people are statistically likely to get fucked as well".
This affects nearly ALL pppoe users, in addition to Charter Communications, Verizon FiOS, and God knows who else. A wink and a shrug isn't showing your best side, but your call.