These are often not disclosed until you start. Day 1 'paperwork' that drastically changes the agreed upon terms of employment well after you have left a previous position. In some cases they are even forced on you after having worked somewhere for a while and future employment is predicated on them. They are evil. I almost quit my job over this, but of course how can you afford to not work while searching? And searching while out of work is far harder than while still working. We need penalties on companies that do this, not just a ban. 'Sign this or you are fired' documents after you are hired should have repercussions.