Are you talking about the recent Panny players like the RP82 and CP72?
From what I understand, that "feature" does nothing(!). Probably something they originally planned to do, but did not implement late in the production process.
The zoom feature is INVALUABLE to 4:3 TV owners. It basically zooms a widescreen movie to reduce the size of the "black bars" on your TV screen. A good zoom feature does 2 things: (1) maintains picture sharpness, (2) provides several zoom levels, like 1 thru 4 (little zoom to most zoom).
Toshiba DVD players do this PERFECTLY. For those of you who hate bars, just buy a Toshiba DVD player and click those bars away.
Just realize that each zoom click is actually chopping of the right and left parts of a widescreen movie. I like Toshiba because you can zoom just a little, to make the bars smaller and chop very little. Or, you can zoom the bars away completely, but you chop off lots of right & left info. Your decision.
AND, if you decide you don't like the zoom feature, then don't use it - Toshiba DVD players are overall good performers.
FWIW, every friend and relative that has asked me for a player recommendation this past holiday season (5 in total and all 4:3 TV owners) now swear by this feature. And before the purist OAR crowd jumps down my throat, they are choosing to use the feature - they are free not to.