Bag 'o awards at the pool…
I agree with Chris in that with or without a ceremony, I am not sure I would have used the pool party setting to hand out the boy's awards earned over the summer. From his description of the event, it sounded like a pack activity/outing (without the elements of a traditional meeting — opening flags, skits, songs, messages of importance, award ceremony, etc. that a traditional pack meeting has). That in and of itself would say it was not a appropriate venue just as one would probably not necessarily hand out awards at a pack outing to say a radio station, baseball game, firehouse tour.
Having said that, I think the dilemma may become when to give out what the boys have earned. Awards should be given as soon as possible after a boy earns it. I believe the new Den and Pack Resource guide goes as far as encouraging the Webelos leader have activity badges on hand to award at the den meeting once an activity badge has been completed and signed off. Not sure about the other ranks though.
I’m not sure I would not hold awards earned in the summer beyond the very first official pack meeting once school has started (or the pack moves from their "summer program" to their "school year program" regardless of when Fall Round up is) just for the sake of a “big show” for the new recruits. I understand the point of having the new recruits see the others in the pack get tons of stuff as incentive to "that can be me next time" but is it fair to hold back awarding the items to the boys who were very active in the summer?
Our schools start mid-August, we have an actual traditional pack meeting & cook out in August right after school starts. Due to scheduling of Boy Talks by the DEs and other things, round up does not occur until the last week in August or first week in September. I am not sure we could hold out until our September pack meeting as that is about 5-6 weeks into school and the "fall routine" to hand out what was earned in the summer.
If you have a robust pack who is working on advancement, the Sports & Academic program and other things, you should have boys getting stuff just about every month which hopefully will encourage those who did not get something this month to work on something for next month.