Also bear/pepper spray is illegal in Yosemite Park. I overheard an REI employee advise a customer of that fact the other day, and just confirmed it: www.nps.gov/yose/planyourvisit/weapons.htm

The rules may be different in Sequoia/Kings Canyon NP. A google search suggests that some pepper sprays may be legal, depending on how they are forumulated, and assuming that the owner/user is 18 years or older.