As Melle says, this does work - mostly. iTunes will treat the files as being recently imported if you recreate the .itl file from the .xml file. This means that you will lose your play count/date added, etc. IIRC, this method keeps your ratings.

This method would also lose any metadata stored in the .itl file, like track artwork (if it isn't stored inside the files).

Could it be this has changed over the years? I did this a little less than a year ago, and my play counts/dates added/last dates played were all in tact, as far as I remember. Not sure about the artwork, though I believe that was all still there as well.
In fact, if I look in the xml file right now, that contains all the mentioned info. Note that the xml and itl file are roughly the same size as well. Though I do have to admit I'm currently at work, and can only check on a Windows box.

I just tried this at work (Windows). It kept the play count and last played date, but lost date added.