“Are they calling lids so that Biden can make appearances without Trump supporters showing up?!”
Probably so he can make appearances without the press asking questions. I believe lids are specifically related to the press. (I am not positive.) That leaves him free to stand at a podium, drool, and make a fool of himself — and then walk away.
That was my first thought....especially since an online search found that the NC rally was announced two days prior.
Biden is gonna play cat and mouse until Election Day.