Casinos in Detroit will be restricted to 15% capacity when they re-open their doors when Governor Gretchen Whitmer relaxes restrictions via an executive order.
The Michigan Gaming Control Board announced the stipulation as they gear up for launches, and the number will be based on the Detroit Fire Department maximum capacity. Poker will also be shut down, and buffets will remain closed during the initial re-opening phase. Detroit's three casinos have been closed since March 16th, when the governor issued an executive order that put into place large a statewide lockdown.
Tribal casinos have re-opened already, and appear to be quite busy, despite using social distancing and reduced capacity as well. These casinos aren't subject to the same restrictions, because they're on sovereign land.
Other states have begun re-opening their land casinos, with Nevada the most prominent of the bunch.