In an alternate universe, the caution sign Children at Play is not what it seems. It’s a warning.
You could use a semicolon instead of a period after seems (but don’t capitalize it’s if you do). Whenever referring to the words themselves (as with the word seems in the previous sentence), italicize them. (You could also write the words of the sign in all capital letters, since many signs are done that way. They’d still need to be italicized, though.)