Im sure the bees are under stress being in a box (Hive), forageing, lack of pollen or nectar, weather can stress them rain/Thunder/freezing temps. Me opening the hive can cause stress and sure wasps would be flying around anyway near the hive, i wonder a bit like my chickens they were constantly stressed by the dog but now they know he cannot access them inside the fence so they dont bother with her. therfore i assume a few wasps confined will not bother the bees surly they will die of dehydration fairlly quickly. maybe the old jam jar is still best.