The things these merchants come up with never cease to amaze me. They seem to pretty much make up their own rules and think that affiliates are at the bottom of the totem pole and work for them.
I have also seen them kick affiliates out the busiest time of the year e.g. Black Friday, Christmas, etc. and then reinstate people when things get slow. What they think it doesn't take time to take those links out and then put them back int? Pffft! Those are the merchants I will never work with.
Tracking seem pretty much an issue everywhere. Some networks more than others. There are so many factors that cause that cookie to be overwritten that I am so tired of it.