Am a Lifetimer and Three Observations:
ACCESS: Went through Narita, San Francisco and Seattle Skyclub flying United on Jan 3, 2019
Narita Sky Club was unaware of the Lifetime exception and originally stopped my entry. They asked for a Delta boarding pass, and when I presented the agent with a United Boarding pass, they had informed me of the changes to the entry requirement. I was happy to show them the revised Lifetime access policy and they apologized graciously, and began immediately communicating this information to all of the employees. Very professional.
SFO Sky Club agent who checked me in did not ask for the Delta boarding pass, as she had thought I had misplaced my boarding pass. Later when I asked for a shower access, she discovered that I was not in the "system" and inquired for my Delta Boarding pass. I told her I was accessing using a "Lifetime membership". She informs me that it was difficult to quickly check for lifetime status as credential do not immediately flag, Lifetiime status. Going forward this might change but currently, agents will need to flip through several screen to identifying a member who is lifetime. The agent had to enter false delta flight number to completing my check-in.
SEA Sky Club:
One last access was with SEA Sky Club. These agents were aware of the lifetime policy change, but they too indicated they had to shuffle through screens to identifying lifetime credentials. The agent that checked me in, had to view the screen which indicated my expiration date. They also indicated that it might not be possible to view this on their handheld app check-in and I would likely need to check-in with the agent.
So access is possible, and agents are beginning to become aware of the policy change, but new hiccup exist due to system requirement and credential not showing lifetime, especially on the hand held check-in. For now, I think the expiration date is likely the best indicator.
Jiburi