I can share my experience with this. I arrived 12/28 at my hotel / lodging, and my first day for
Disneyland is 12/29. I went on 12/28 night time to exchange paper voucher for actual Disneyland tickets. On 12/28 night time, TS parking lot wasn't doing security, and after arriving Disneyland by Toy Story Shuttle buses, I too was wondering the same thing, if we would have to do double security, because it looked wide open at the drop off point to the Harbor security entrance point.
On 12/29 early morning, they did security checks before you can get on the bus. They moved the pick-up location from Woody down further (I didn't pay attention to what the name of the lot there is). That was the only place they were picking up from, so you don't have a choice, to ride the shuttle you have to go thru security at Toy Story. When we arrived, there was new barricades separating the TS bus drop people from those entering from Harbor, so you can just enter without going thru security again. When we return back, they dropped us off at the security pick up location, so we had to walk a little bit further for Woody lot.
On 12/30 when we went, they didn't do security checks at TS parking lot. They herded everybody to the Woody pickup location. When we asked CM about security the day before on 12/29, he said it was just a test run to iron out the kinks, that they aren't doing it permanently yet. He said there will be another test run later that week. When we arrived at Disneyland, the barricades weren't there anymore, and we had to contend with the crowds of people entering from Harbor (and boy, was it a lot of people). Upon return, they dropped us off at Woody pickup area.
On 12/31, they ran security checks again at Toy Story parking lot. After my experience at the main security check points at Harbor entrance the day before, I much prefer the security checks at the TS parking lot, as they were a lot less people to contend with.
We went again on 01/02/2020 and 01/04/2020, and both those days, they didn't run security. So for now, it's not a permanent thing, and was told it will be as needed by CM, but that they are still in testing phase.
Great3