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.
The 372 calories in one serving of Pioneer Choice Philadelphia Sushi Roll are equivalent to the calories burned while: Running (6 mph) for 31 minutes. Stationary rowing for 1 hour and 5 minutes. Chopping wood for 49 minutes. Sleeping for 5 hours and 28 minutes.