Broadback writes
Love eating out this weather, but since receiving multiple wasp stings
a few years ago I have become allergic to them; this means that I am
very anxious when wasps are about, so cannot enjoy eating out as I did.
SNIP
Secondly is there any way to keep them away from the table area? I know
that jam jars with a little jam and water act as traps, would that work
to attract them away from the table? Any help would be appreciated.

They seem to be particularly attracted to yellow. We were once at a
barbecue, and a woman arrived in a yellow dress: within minutes she was
absolutely covered in wasps. She rushed home and changed into another
colour, and was all right after that. Since then we have avoided yellow
tablecloths, umbrellas, and especially clothes....

--
Klara, Gatwick basin