Water balloons?

[cantab]

Originally Posted by DX

You also want ALL the tools of war at your disposal

At the level of an army that's correct. However, at smaller levels, considering a single person, or group, or even the entire team if it's small, 'opportunity cost ' comes into play. Yes, a WBL may have uses. However, you have to ask yourself things like "Should he take the WBL, or the CPS 3000?", or "Should I take water balloons, or a refill bottle for my gun?".

I've yet to hear of a truly large 'serious' water war, mostly I think it's just small skirmishes. In such, you want every person to be as effective as possible.

[DX]

Having the option open doesn't equate to using it, just that it's there if necessary. Personally, I wouldn't have anyone carry a launcher as a primary - they'd either have it disassembled in a backpack or cached somewhere on the field that may be a good place for a one-time attack.

Obviously organized wars rarely exceed 20 total participants, but what they arm with really depends on what you aim to do. A strategy heavy with trick tactics will see lighter armaments and more balloons, while a strategy focusing on versatility might see a variety of weaponry and gear.

[cantab]

Yes, having less-used weapons placed in bases or caches might work. The problem then is can the person get to it and use it before the opportunity has passed.
As for carrying anything disassembled, that's something I'd try and avoid if possible. How long would such a thing take to put together.
Of course there will be some people who will make relatively light work of heavy loads. These can be the people you give the 3000 AND the WBL to!