hrrrmm....Just a thought, if a bodyshop re-spray a panel without doing any sanding/scuffing/etc., it goes to show that bodyshop is cutting corners and not doing a proper job, wound't it? A 'proper' re-paint would be to sand down the panel until the base coat before re-painting, isn't it?
Anyway, I've used CQuartz and still have a few panels of my car wearing it. Not that difficult (relatively) to remove. Though difficult to be remove chemically, mechanically it just need a mild polish.