Just received my first acrylic kilt

[The Wizard of BC]

Just to clarify What defines a traditional kilt, is what is hidden behind the inner liner. The liner is only there to hide the internal construction elements.

Wool is a dimensionally weak fabric. If you pull on the bottom you can see the fabric stretch and distort. If you add that the hand stitching of the Fell is weaker than machine stitching, and that the inner portion of the pleats is cut away to reduce the bulk, something must be built into the kilt to resist the stress of strapping the kilt on and wearing it.

All clothing used to have interfacings. This is to allow the outer decorative fabric to drape naturally. A kilt has full floating interfacing just like a custom made suit coat. The interfacing also adds vertical stiffness to the garment. The back of a traditional kilt will stand up on its own.

A kilt also has a stabilizer strip. This is a horizontal strengthening element. The straps and buckles are sewn all the way through the outer fabric and anchored to the stabilizer strip.
If you grab the buckles of a traditional kilt and pull you should see no stretching of the Fell area. You should never transfer the stress to the outer fabric or to the stitching.

All of this is then hidden behind a liner. Many people think that the liner is to keep the kilt clean. Well, if that were true the liner would be removable and cleanable. Many of the casual and Pub style kilts have a liner but only because a traditional kilt has one. In fact we define a Casual and a Pub style kilt as one that will look from the outside like a traditional kilt but which lack or have minimal of the internal constructions elements.