DM going after Vivitar makes sense to me. Go after the smaller infringers first. It is more cost effective to go this route and get a win from the Courts. This is also the path of least resistance.

To go after the big companies first would most likely cost a lot more because they would likely put up a fight with all the money they have at their disposal. This is the path of most resistance.

When the smaller infringers bend and the courts rule in OUR favor then DM can approach the bigger ones and say to them " Go ahead, make my day, cause you don't have a chance"

I love it when a plan comes togher.