A typical legal rationale for protecting the consumer is based on the notion of policing market failures and inefficiencies, such as inequalities of bargaining power between a consumer and a business.
It sounds kind of expensive when you first check out, but it's actually pretty cheap if you consider it. Take something standard like a Philly roll (nori, salmon, cream cheese, cucumber, avocado). At Maki it will cost you $6, but the roll is pretty fat and you get 10 pieces. Most sushi bars charge around $5 and give you 6-8 pieces.
For other uses, see California Roll. A California roll is a makizushi, a kind of sushi roll, usually made inside-out, containing cucumber, crab meat or imitation crab, and avocado. In some countries it is made with mango or banana instead of avocado. Sometimes crab salad is substituted for the crab stick, and often the outer layer of rice in an inside-out roll (ura-maki) is sprinkled with toasted sesame seeds, tobiko or masago.