Online customers who order certain bulky / heavy items should not be able to choose lettermail as a shipping option.
It would be nice if crystal commerce would let us only allow the lettermail (stamp and envelope) to be selected if the items in their cards are singles, and there is less than ten of them. Even though we have "MTG singles only" in the name of the option, we are regularly cancelling orders from customers who either inadvertently select this shipping option, or deliberately selecting it in the hopes we don't notice in order to save money. Shipping is very expensive in Canada, and we are already struggling to line up our shipping rates with orders. Our post office has additional charges that are not included in their official rates (fuel surcharges) that vary depending on weight and size of package.
A universal option to exclude products from shipping options is also necessary for things that are flammable. You can't ship anything flammable via expedited, they must go ground.
I concur. With things like Dice (Dice Masters), they are light enough to qualify for letter. I had to change the packaging preset to something heavier than actual so that international customers couldn't pick letter.