Metallica loves money, if they can somehow tap into a new market of kids that buy their music bc of an association with Bieber, they will jump on it. If Bieber likes it, Im sure many of his fans will check them out if they havent heard of them yet. Biebers endorsement is sort of like Oprah's book of the month selling power. Metallica will do anything to make more money, no matter what it does to their image or if it upsets a portion of their fanbase. At this point I would be more surprised if they turned down money for anything, no matter what it does to their image or if pisses off long time fans. In many ways I dont blame them, it is tough to turn down money even small amounts, but they were already very well off before completely selling out to the highest bidder. They just wanted a lot more money or more than likely their wives wanted more, like Sharon pimping out Ozzy.