It is necessary for the butcher to prove that he is aware that the kosher stamp on the carcass means the meat is kosher but does not preclude further treatment. This assumption is made by too many butchers and consumers. After all, many consumers are not aware that many butchers do not kasher meat as a matter of course. In fact, even butchers who kasher at a customer's request frequently do not kasher steaks and lamb chops because they assume that the consumer will broil them anyway, and will kasher them in the proper broiling process. The butcher, however, has both the legal and moral obligation to inform his customers.
Rabbinic supervision provides the basis for a consumer's confidence in a butcher.
The trustworthiness of some butchers is suspect because of their practice of selling certain brands of chickens processed in warm water. Most authorities feel this cooks the blood so that it cannot be extracted by soaking and salting. The same person slaughters the chickens, supervises his own slaughtering work, inspects the chickens after slaughter, and oversees the processing of the chickens. In reliably certified plants, these jobs are performed by at least four people. Finally, unlike the widely accepted brands of kosher poultry, the chickens from non-recommended plants are not always kashered prior to distribution.