Correct answer - never.
Trade marks are valuable assets of a company and they should not be misused.
So why do companies trade mark goods ?
- It is a way of identifying a unique product
- It shows commitment to a product
- It helps protect shareholders
- It helps protect business partners (they have a lot of skin in this game)
- It helps protect the employees
- It helps protect the Brand
and finally, it needs to be done to keep the trade marks - you can't selectively enforce them.
IBM is the second most valuable brand in the World.
I know they are deadly serious about everything listed - it's time others knew.