If the owner/renter of the apartment is present and living there then it is not illegal.

But there are leases/coops/zoning regualtions that prohibit commercial activity such as this.

My question is always, would you like someone from another town and conducting illegal activities where you live?

I understand what you are saying. At this point we are committed to the rental. From what some of you are saying there won't be and option for this in the future unless some other sanctioned option is put in place.

So now we're looking at walking food tours. Any advice?

Foods of New York...google it; we did their original tour, the Greenwich Village one...very fun!