Actually, you can under several circumstances.
From what I remember reading when the new pocket knife laws came out
you allowed to carry one for the following purposes:
- Work
- Sport
- Religious
- Consumption of food (they gave peeling fruit as an example)
- Collecting

Define religious? a lot of allah's people would consider stabbing a
westerner as religious as praying six times a day. Not to mention the
mormons - hate to think what would happen if they had guns.

-mark