Well no, but short of a rewire, a gfci with sticker is the code-compliant way to plug in three pin plugs to an ungrounded receptacle.
A rewire is the right solution but utterly impractical for many. Just silently swapping in new receptacles and leaving the ground unconnected is easy but not compliant. This is the middle ground.
Hi, poll worker here and this is absolutely accurate. If you stand in or near our polling place we will absolutely have you removed.
However… observing polls is a core part of a functional democracy and I strongly encourage you to do so. Each county is a bit different, but essentially every single one of them have some sort of process that you can register as an observer and you’ll be legally protected while observing and documenting what you see. If you’re affiliated with a political party, contact your local officials and they can help facilitate, as most observers are party affiliated.