Continuing the discussion from Global Scripts:
Shouldn’t it say
$(“.page-sales-preview #chkcal_reminder”).prop(“checked”, true); ?
The code sample is correct, it should be .chkcal_reminder as it’s using a class selector rather than an ID selector (#).
The check-boxes are named differently on the purchase screens vs the sales screen. It was never originally intended to be exposed to users so the subtle difference didn’t matter.