I totally agree with you. A three foot common king (any sub-species) can easily handle an adult mouse. In fact my 3' easterns usually feed on 3 jumbo mice per meal or a 5"-6" rat. To feed a snake of that size hoppers is kind of silly, not to mention a waste of time, money and fat calories. Also, contrary to popular opinion, all of the snakes that I have seen on the multiple hopper diet, you know the diet that is supposed to achieve a good growth rate in young animals, are short and fat.
Snakes (mine anyway) grow when they are fed large meals on a regular schedule, every 1-2 weeks depending on the particular stage the snake is in (growth, reproduction, recovery from brumation). If they regularly eat this way in the wild, why shouldn't they be able to do the same in captivity? There are two reasons why snakes puke from large meals, and both are directly related to husbandry. 1. Disease/parasites 2. Inadequate temperature choices. Both of which are controllable by the keeper.
I absolutely agree that regurgitation is very, very bad. I also agree that one should feed a snake that has vomited very small meals infrequently, until the animal's GI tract is healthy again (possibly several months).
But the notion that a 3' common king cannot handle a large adult mouse is laughable. My 33", 2 year old Burlington Co. NJ eastern female just ate a 5" rat last night. She does this every week. Interestingly, she sometimes chooses the cooler side of the cage when digesting and sometimes the warm side. Oh yes, my yearling easterns, at 24"-27" eat small adult mice no problem. It may take them 30 minutes to get the meal down, but they keep it down, they digest, and they are bigger the following week when they are hungry again.
I guess feeding small food items frequently in not necessarily wrong, I have just found it to be counter productive. Everyone should experiment a little, and learn from observing their animals regarding which feeding method is best. Please don't just take the word of the jacka$$ at the pet shop.
From a former petshop jacka$$
(Will)