Uhm guys maybe you should take another look at that banner rule...
It doesn't say you can't have them...it says don't use them to save seats or hang them on the pit walls. Bring them to the field, hold them up to cheer, or hang them in your pit...all is not lost!
Nor did they say you can't bring water...they said you can't PROVIDE TEAMS with water AS A PROMOTION. You can't give out "team water" basically.
Atleast that's the way I read it.