Legacy99- Thanks! The reason for the solvent and alcohol wipedown is to ensure that there are absolutely no traces of previous waxes, polish residue, oils or silicones that may be present which can interfere with the polishing process. Some products (especially silicone) tend to deeply embed themselves in the paint and are extremely difficult to remove. A clay bar will only remove bonded contaminants from the top surface of the paint, but the use of a solvent / alcohol really seems to break them down better.
Makes good sense, Thanks.