Its not increased that has been illegal for a long time. They found a way around it though and of course nothing is being done. Its called dynamic range compression. Basically they cram the entire ad at the maximum legal volume level so it sounds lounder.
Yes I did hear something about passing some limiting law, not sure when.
Of course, as you mention, they can just peg the sound levels in across all frequency bands on all tracks in the ad, and yes, it does sound louder that way.
Of course, if they actually want to get people's attention so they try to listen, they should whisper.
