Given the intelligence of the average person, warnings like this one are no doubt helpful. Anyone who has ever had to fish out a brown trout knows it is an unpleasant task.Welcome to our ool. Notice there's no P in it. Let's keep it that way.
I remember a sign like that from the swimming pool I went to once in a great while as a kid. I always wished they'd had an additional sign that read simply "welcome to our l. . . . " I'm sure all the other eight-year-olds would have agreed with me there.