It can occasionally happen, although I think is still very much the exception. I’m not sure whether this is fact or mere perception, but IME a domestic 767 service or later arrivals seem to be at slightly more at risk of bussing. A couple of times, I’ve ended up parked at the remote stands on the southern side of T5A. And once we ended up at T3 with a fairly long trek back to T5...the driver even becoming confused at one point, almost dropping us off at international arrivals, before a quick-witted passenger pointed out to him we were a domestic arrival before he had a chance to open the door (good thing as I didn’t have a passport since that was a purely domestic trip for me).

But even at that it must be well under 5% of domestic arrivals that require bussing, so even if this were an issue, I’m not sure it occurs to the extent that it warrants a significant redesign of the T5 arrivals flow to account for what must be a small % of edge cases.