Boardwalk Tigger said:SW serves peanuts on the plane. In all the many years I have flown I have never heard of a peanut warning on a plane. Sorry but that isn't going to happen!
I am pretty sure it does happen. I have read a post on this board from a woman who spoke with SW regarding her child's peanut allergy. SW told her they would refrain from serving peanuts and would make the announcement. This particular mother felt that was NOT enough (As I recall she wanted SW's assurance that NO peanuts had been served all day on the plane and their gurantee that no one on the plane would eat a Snickers bar. SW of course could not meet those requirments so I guess she drove)

We were also allowed to pre-board so I could wipe down everything that he would come in contact with. The flight attendant gave us blankets that were still sealed in plastic, which I covered his seat with as an added barrier. He also wore clothing that covered everything except his neck, head, and hands as another precaution. 
Thank you twinklebug, for trying to save my thread! I got the answer I was hoping for, thanks to everyone who answered my question.
That's why I love this board. You learn all kinds of things!
I'm sure no one is offended, food allergies can be a very real problem for some, so this is valuable information folks are offering.
Yum!