Customers better smile for the camera when they pick up lye at the big chains. Since all transactions at the cash registers are filmed, all Big Bro has to do is ask the stores for the copies. Lye is an ingredient used in making meth. God forbid you have allergies and need a decongestant. :)
Thus, if some bozo is going to make methedrine, in theory he should have no trouble whatever making sodium hydroxide as a precursor. Filming purchasors of NaOH in order to prevent the manufacture of methedrine must be one of the grossest examples of wasting time and money.
Note to would-be manufacturers of NaOH: prefer making it outdoors, absent a top-quality ventilation system, and definitely be well-masked and -gloved. And make sure you combine the reagents DOWNwind from yourself. Wouldn't want to cough up a lung, now would we?
In short, only a competent chemist should try making NaOH; it's easily done, but one MUST know what one is about or else suffer severe physical damage. If someone isn't up to snuff here, buying NaOH will hold similar risks. You could ask the Drano people for a real-life, and very expensive, example of this.