A lot of people are bad mouthing the Red Hot Chilli Peppers because Flea and Josh didn't have their insruments plugged in. As it turns out they didn't really have any choice in the matter:
No trickery. No choice, but no trickery— Flea (@flea333) February 4, 2014
It appears as if the producers of the halftime show had the instruments playing on a backing tracks and not live. It also appears as if the vocals were indeed live. Flea and Josh both removed their wireless transmitter packs so that in the event that someone caught on they could say... well, exactly what Flea tweeted: "No choice, but no trickery." It was a brilliant move on the their part, but they weren't the first to mock TV producers.
Way back in 1991 Nirvana played a very popular Brittish TV show called Top Of The Pops. The producers insisted on the band playing to backing tracks and have the vocals be the only LIVE part of the performance. Watch Kurt's slow exaggerated strum patterns. Listen to him drop his pitch and change the opening lyrics. Watch Dave grohl hitting the wrong drums on purpose. THIS is quite possibly the greatest middle finger of a "live" performance in rock history.