I got this info from a PhD at our old Pink Flamingo!!
"A stock buyback is not a magic bullet. If you are a firm that should not be doing buybacks, don't go down that road, even if every other firm in your sector is doing so. You may be able to fool the market initially and get a stock price pop, but the truth will eventually come out to hurt you (perhaps after the top managers have cashed out their options and moved on.. but that is another story...)"