Originally Posted by
bzcat
Looks like I may be over thinking the 5kg carry on limit...

Given I searched ad nauseum, just flew USM to BKK on the A319. We only travel HLO and decided not to take my Keepall because of the 5KG HLO rule on our two flights.
On neither flight were our cabin bags weighed. In fact, there are several pax with multiple bags, strollers etc.
USM has a separate J trolley to the aircraft.