Dress is an important part of presenting a professional image. The stereotypical image of a piper in full military style uniform, complete with plaid and feather bonnet, is no longer relevant today. The Piping and Dancing Association of New Zealand maintains a number of bylaws for dress, and these can be found here.
Today, solo pipers typically have the following items of dress:
3. Cut away jacket
4. Ghillie brogues or school-type black shoes
5. Long socks (hose)
6. Plain shirt and tie
7. Bonnet or glengarry headwear
Typical dress examples can be found here. Pipers are expected to be correctly dressed when competing, complete with headdress. This is an important part of projecting a professional image.