yea this method is new to me, just read through the thread last night/this morning. but i've dyed clothes using rit dye on several occasions.
presuming you don't try to drink or bathe in the stuff there are only 2 things you should be concerned about. first is, well, it is boiling water lol and second, this stuff will stain your fingers and any clothes that it may splash onto. so you'd need to wear some type of gloves so your hands don't get stained.
a number of people from that thread use pots they use for everyday cooking, they just clean them out real well before using to make up dinner. lol

if you do decide to look into this option further, i would highly suggest that you read the first post and at least skim through the rest of the thread. that way you can get some input from other peoples trial and errors. ~_^

if you do give this a shot, make sure you post up some shots of how it turns out!!!