Hi, ready to update on how things went with the Costco 4-day park hopper.
We purchased them along the way at a Santa Clarita Costco off HWY 5, didn't have any issues there and was not asked to show ID - though we chatted with a man from St. Louis while inside Disneyland who was also using the same hopper, and he said he was asked for ID at the Costco he went to and was not able to purchase them (can't remember which city!). The man's son lives in So. Cal. so the son ended up having to stop by later to purchase them. The St. Louis man also mentioned that he had been at the park since earlier in the week and had not had any issues or ID inquiries, said it was not his first time using a discounted So. Cal pass (other passes, not only the Costco pass), had used them many times and has never been asked to show ID.
First day Friday Oct. 23rd, my cousin ended up being the one to walk us to the gates, he stood by in case there were any questions, stopped by California Adventure first, then later hopped to Disneyland - we were not asked any questions, asked for ID, nor asked to sign at either park on that day. We had a total of 3 Costco hoppers, the rest of us were annual pass holders - and yes you can go directly to the turnstile without redeeming them at the ticket booth, Costco will set you up with what you need.
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Second Day, Saturday Oct. 24th: Now on the 2nd day only one person was asked for ID

, so now I do believe it just depends on the cast member, though it does seem like most cast members do not ask since this was not our first time using So. Cal passes.
My cousin nor aunt were available to join us on Saturday, but did feel a little better about being alone since they had not asked for ID the day before. But we decided to split the group up instead of presenting 3 Costco hoppers at once to the same CM, just in case it seemed like too many or a little odd to the CM - we were a little paranoid by then

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Each person was paired with an AP member, and each lined up with a different cast member, only one asked for ID. My other aunt was the one asked, she's elderly, doesn't drive and personally has no reason to carry ID with her so she did not have any ID to present - the AP holder with her panicked and quickly walked away

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Aunt doesn't speak english, I don't think the CM spoke spanish so I don't think she was interrogated or anything like that - she was simply asked to sign the back of the ticket. We were too nervous to park hop after that so we stayed at Disneyland for the entire day. The passes have 2 days left on them which will be used later on in the year or next year, and yes by the same people.
My dad and I exited the park afterwards to run over to Guest Relations to ask a question regarding something entirely different, and upon return we decided to line up with the inquiring CM. The lady in front of us presented a free admission birthday ticket - it was the hard ticket, she had already visited the ticket booth for her print-out exchange, and the CM asked to see her ID! For some reason the lady didn't have ID on her person, she said someone else had it so she had to step out of line to get it, cast member thought it was odd and mumbled something like "well she had to show ID to get the ticket, why wouldn't she have it with her".
My conclusion is that this particular CM is one of the few who does follow the rules and takes time out to follow policy, she did also seem to have a stern attitude. I would post a description and name for those who would like to avoid her, but I think it's best to share this via PM, so if anyone is interested feel free to send a private message.