Fair enough and agreed, but moot as you point out there's really no comparing a container plant to one in the earth -- they are completely different environments worthy of different considerations. Bottom line, the argument that "I don't flush my in-ground plants therefore flushing is also useless in container plants" doesn't really stand on its own.Salts will buildup if you're using some bottled fert product, which isn't natural soil, and so a flush would probably be a great idea.
Incorrect. Rain will not flush a plant like is done with containers. Plants aren't flushed in nature.
If you have been using ferts, then flush. If using natural soil, no flush.
+rep for getting it.