One at Shanghai's Oriental Pearl Tower reads: "The ragamuffin, drunken people and psychotics are forbidden to enter."
A Shanghai hotel, meanwhile, advises guests to "leave your values at the front desk". Another at Beijing's "bird's nest" stadium reads: "Tender, fragrant grass. How hard-hearted to trample them."
Beijing made efforts to correct solecisms in the run-up to the 2008 Olympics. Shanghai is now launching a similar campaign before it hosts the 2010 World Expo.