ALTER TABLE ... AUTO_INCREMENT = NN; should return a Warning if it can not use the provided value

The syntax ALTER TABLE ... AUTO_INCREMENT = NN can assign a new value to the auto_increment table option, but the assigned value can not be lower than current MAX() value within the column. This is not explained in the KB.
Such ALTER always returns without any error and without warning which can be misleading. There should be some warning like:
"Can not set AUTO_INCREMENT to NN which is lower than current max value of XX"
or at least:
"Can not set AUTO_INCREMENT lower than current values within the table"