Don't pick up heavy weights like groceries or children with straight legs.

So why does this instruction not want children with straight legs to be picked up? The problem is with the punctuation of the sentence!!
The correctly punctuated sentence is given below:
Don't pick up heavy weights- like groceries or children- with straight legs.

Apparently, this appeared in the Eastern Evening News. 

There is another classic experiment which was conducted by an English professor who wrote the following on the board:

A woman without her man is nothing  

and asked his students to punctuate the sentence. 

The female students punctuated as follows:

A woman: without her, man is nothing.

The male students punctuated it as follows:

A woman, without her man, is nothing.

The 2 sentences have exactly the opposite meanings! Punctuations are important!!!