As the customer I would not shop with a merchant who was...

As the customer I would not shop with a merchant who was charging the surcharge (if it comes to that which I highly doubt in this early stage of BNPL, if ever) and simply take my business to one that isnt and get the product cheaper. Merchants would have rocks in their heads, if what current merchants are saying about increasing their business volumes due to having APT then they run a huge risk of loosing money. Smaller profit on larger volumes still = larger profits.