While the "rules" have changed a great deal since the 60's, there is still a significant segment of our society which demands, not asks, that the "rules" be followed. I had constant dealings with them before I retired, and always dressed to their standards. (I was asking for money!). My general rule was; It is better to err on the side a "traditional" than go too far the other way. (I always a wore a three piece outfit, not always matching colours but always tried to look "conservative" doing so.)

To my mind (and taste) there is nothing more traditional than the "tank". That is why I think the piper in question is a bit overdone. Especially with the rank on the sleeves. If it were a military mess jacket, then the rank would be appropriate. Is it?