2-3 seconds is tame. I played a game earlier where I started a four-pass play, it got picked off at the end, they were skating up ice and their Shark RW caught me coming out of the zone and just thugged me for an injury and no call. Fully 10 seconds, without exaggeration. I'd tie up for the faceoff win, never touch the puck, our winger would be heading up ice and this guy would just come flatten me behind the play for no call. I spent the whole game low energy with Elite Warrior on.
I'm hesitant to even refer to it as an exploit, as when it's abused to the fullest it's essentially cheating. The interference timer should be one second, max.