Depending on the city and state, this could be illegal. I'd encourage you to ask the server if the 40% goes to the kitchen or the owner. If the latter, write a letter or make a call to your labour law enforcement group.
https://www.dol.gov/whd/regs/compliance/whdfs15.pdf
>A compulsory charge for service, for example, 15 percent of the bill, is not a tip. Such charges are part of the employer's gross receipts. Sums distributed to employees from service charges cannot be counted as tips received, but may be used to satisfy the employer's minimum wage and overtime obligations under the FLSA. If an employee receives tips in addition to the compulsory service charge, those tips may be considered in determining whether the employee is a tipped employee and in the application of the tip credit.
[1] http://www.tipcompliance.com/polLearningCenter.cfm?doc_id=89
Probably not. In the restaurant I worked at was customary for the waiters to tip the kitchen and support staff. Owners were not tipped.
http://www.seattletimes.com/life/food-drink/seattle-restaura...
The implication is that not only is this restaurant, which we ended up paying ~$80 a person to eat dinner + wine + dessert at, screwing their customers with the mandatory service charge, they're also screwing their employees by keeping 40% of it for the owner. I won't eat there again...
Edit: Added visual proof (and name and shame): https://s3-media4.fl.yelpcdn.com/bphoto/t3UUaCU8gl6zPsVQghlv...
I would be happy to learn that the 40% was going to the cooks. It's still a shady practice, and what makes it worse than not informing your guests ahead of time is that they're doing this in the name of "providing a livable wage for our staff." Pay your staff a livable salary and stop screwing your customers over...