why shop keeper doesn't just kill them.do they claim they have money?
My guess is either because it would be unseemly, because it'd be a pain in the ass to clean up (which he would probably have to do), or, if you look at the size of that Marisa, those are some pretty hefty yukkuri...
Probably the second reason.
That's probably some ridiculous and exaggerated puff-puffing, but if its able to pick up a donut with tongs, there's at least some matter behind it.
Maybe he wants them to realize the donuts look like yukkuris.
Looking over the other pictures, I think that Marisa at rest is probably approaching two feet wide... Compare it to the door when it walks in, or its height to the height of the table. So I'll stick with my previous theory, or two of them. That is a big-ass Marisa (maybe we've found the missing link between normal and dosu?), which would be hell to clean up after. (Being a food shop, he'd have to not only clean up afterward, he'd probably have to toss most if not all of his inventory if he were to go after Marisa with the gusto with which we have become accustomed.)
They come to buy doughnuts they even show him money. so they're a customer...
Yukkuri is also this store's mascot. so he don't know if he could kick them out or not.
When did they show him money?
On the 3rd page, the Father Marisa says "Marisa's family came to buy mister donuts, da zeeee! See? [We] have proper money, da zeeee!" and the Cashier replies ".....Oh. Pardon me. ......"Credit platina for translation.
-late response is late-
2.Marisa: Fuuuu!! Fuuuu!! (Huff puff?)
Thought: She can barely even do it!
5.Cashier: Umm, ma'am, maybe you'd better let me...
Forgot a part:5. Thought: It takes her too long just to take a single donut!