I would go with the OFFICIAL stance on wearing military uniforms.

Unless you are active/retired member of any branch of any military in the world, you have no business wearing OFFICIAL uniform items.

Now, since this tartan is not official in any way, I see no problem with anyone wearing it.

99.9 of the population has not served or has any connection to the Polaris so unless there is a sudden massive amount of knowledgeable people asking abut the tartan, again, I see no problem.

This is not the UK and there are no rules or actual legal repercussions on wearing such items.

Some people I guess just see too much into things.