[QUOTE=Mdcastle]
Back in the day, were receptacles always wired with the hot on the right, so such an adapter, assuming diligent use, wouldn’t create a hazard?
[/QUOTE]
Back in the day, it was common for receptacles to be installed horizontally so you just have to be careful.
For the OP, I can’t tell if theseare polarized or not, but you can probably buy a fistful of them and a file or a pair of “dikes” to “depolarize” them if needed, and snip off the useless grounding tab. . Also probably cheaper than travel plug adapters.
Alternately, a small old neighborhood hardware store might still have non-plarized adapters. These things used to be ambidextrous…no idea when they changed the design.