Comment by dghlsakjg
This is a dilution not abandonment issue.
Courts will look at the level of systematic tolerance. If you have a history of vigorous enforcement, it will be harder to argue in the future that a borderline dilution should be allowed.
If you allow borderline dilution, the court is going to consider what you have let other people get away with in the past.
It’s a bit of a catch 22
I would still be interested in a real case where a trademark owner ignored a borderline case and this later resulted in an adverse ruling when a more concrete interest was at stake.