Yes, the signs of "Swimming and wading are prohibited"

they walked around the fence and swam in the seemingly calm water. The body has not been found yet after almost 2 days.  

During our lunch break on the way to Glacier Point, we met a group of 6 teenagers from Santa Cruz. They bragged that they hiked an abandoned trail straight from Curry Village to Glacier Point even though there are a few signs of "Hiking is prohibited". They had to scramble and rocks in some sections are loose. They were luckily successful this time and hope they have this kind of luck all the time. But, it is not worth taking the risk. Anyway, Teenagers think they are invicible. 初生牛犊不怕虎.