I saw this on a sign in a restaurant.

Problem:
This imperative implies that the reader will not be served until the host is seated.

Explanation:
To appreciate the problem, let’s think a second time about this imperative.

“Please wait for some event.” is the template for this imperative, in which “the host to be seated” is “some event”.

However, the sign writer does not want simply to tell the sign reader to wait for a “the host to be seated” event. The sign reader would not know why he must wait, and waiting until the host has sat down would not make sense.

After all, a host usually stands, often greets restaurant patrons, sometimes walk the patrons to their dining tables, and continues to stand after returning to the lobby of the restaurant. In other words, patrons waiting until a host has sat down would make no sense; restaurant hosts usually stand throughout their work shifts!

Instead, the sign writer wants to tell the sign reader to wait until the restaurant host helps him instead of the sign reader seating himself at a dining table in the restaurant. The host is in charge of walking restaurant patron to dining tables; patrons may not seat themselves.

Solution:
“Please wait to be seated by the host.”