I'm not sure, but for the IG folks to arrive at TT prior to those from the front of the park--maybe so. Then again, it could be buses not arriving until just prior to opening and those driving being held at the parking gates until closer to opening.
I feel very strongly that Disney is staggering buses for opening at the various parks, i.e., YC first bus doesn't arrive until 8:20 a.m. for a 9:00 a.m. opening BUT the true opening has already occurred at 8:00 a.m. Those who have been queued at the YC bus stop since 7:00 a.m. (and second family in the queue) KNOW there has been no bus until that 8:20 a.m. bus and still all those waiting (the queue went from the bus depot to the entryway door) are now late for rope dropping. Other resorts had buses arriving and departing as the YC bus arrives at the park (late). Meanwhile, those who were smart, bailed and Ubered/Lyfted were far ahead of us in the ride queues. Yep, that happened to us to while we were there!