Water Guns Full of Hot Sauce
Anyone who knows me knows that I love my firearms. When it comes to self-defense, there really isn't anything better. I wouldn't advise any preppers to plan on not having them in SHTF. But there may be times when lethal force isn't advisable or required. In my group there would likely be people such as my very liberal sister in law and mom who would refuse to use firearms for their own stubborn reasons. There would also be young kids who wouldn't have any firearms experience and be too young to teach. Even if you stockpile lots and lots of bullets, during a long term TEOTWAKI situation bullets may eventually run out. There would also be the real prospect of gun confiscation in a long term civil conflict of any kind. For all these reasons, I think it makes sense to have some kind of nonlethal self-defense tech on hand.
Anyone who has used bear mace or pepper spray knows that they actually pose a threat to the user. In the wrong wind someone using spray could easily end up disabling their own vision and ability to fight back.
Water guns are cheap. You can get a decent one for ten bucks. Hot sauce in your eyes is just as disabling as pepper spray. It seems like stocking up on several restaurant sized bottles of hot sauce and enough water guns to arm a small army could be done for about a hundred bucks. Another great thing about hot sauce is that it is a renewable resource. The ghost pepper, one of the hottest peppers in the world, was developed by the Indian military to be used as a source of pepper spray. Peppers are easy to grow and produce prolifically. The capsaicin in the peppers acts as a natural preservative. Ghost pepper juice, due to it's incredibly high capsaicin content, will keep for the better part of a decade if stored properly. So as long as your water guns hold up, if you had a place to grow the peppers, you could have a renewable source of ammo and a lot of hot sauce, which will likely be a valuable trading commodity in SHTF. Nothing makes beans and rice taste better than some hot sauce.
It's likely that murder would remain a criminal offense even in a long term SHTF situation. The local governments would still do their best to prosecute and make examples of murderers. You can't ever get a murder or attempted murder charge for spraying someone with a water gun full of hot sauce. You could put a water gun in the hands of a small child and they would be way better off against attackers than if they remained unarmed.
Of course, in any kind of self-defense situation it is way preferable to have actual firearms at your disposal. But what about people who you don't trust enough to hand a firearm? In SHTF every person you give a firearm or bullets to could end up being a threat to you or your family. There could be someone with valuable skills, like a doctor, who you need in your group. You may encounter someone who you are moved to help for whatever reason. A water gun full of hot sauce would be a weapon you could put in their hands on day 1 and you could know that they could at least try to aid in defense if such a situation arose. Even if the government started confiscating guns, you could bet that they wouldn't be enacting water gun control.