Thanks Nelsona, I don't really want to argue with you, you have been a big help for a lot of us and I really appreciate everything you do on this forum, I just wanted to see if you have found some official (.gov) documentation about this rule.
Let me share my experience, I am actually working in Texas on a TN and I visited my parents 3 weeks ago with an expired TN Visa, the POE officer first didn't want to let me in and I showed him "9 FAM 41.112 N8" document and my I94 where it explains all the rules and conditions for the AVR process and told him that I am an ocassional visitor (not a daily crosser) and that I have a legit work in the US that I need to attend, so he read the document and made some questions to another officer.... at the end he let me in (WOW!!), I accept that I was lucky because I am not a lawyer and no one wants to discuss with a foreign officer about foreign laws but this is what it makes me doubt about this unwritten rule.
I will try it again, but foreseeing possible scenarios of needing to schedule an appointment to get a new stamp. If rejected I would even try to cross from a different bridge since it seems that there is not a rounded criteria to apply for this situation.