The MacLaren tartan is a connection to the beginnings of Scouting as we know it today, world wide. Where allowed, the kilt and appropriate tartan in association with the Scouting uniform, pay homage to those beginnings.
Personally, I think there are still too many hangups in American Scouting regarding kilts. Perhaps a good dose of education, "exposure" to the kilt and even wearing the kilt would change the minds of those in charge.
BTW, my son is a Tiger Cub and I'm the Cubmaster and a Den Leader. For November we will be wearing our kilts at the monthly Pack meeting as part of the heritage theme for the month and encouraging the other scouts in our Pack to wear the dress of their heritage.
As soon as I get the opportunity to complete Woodbadge, I'll also get a MacLaren kilt and wear it when appropriate.

Cheers