Is it overkill?
As you are seeing from most of the posts, if you carry more than some other gun person, it is overkill. The reason why is obvious. We all make the most reasonable decisions and anyone who does more than us is obviously in the realm of overkill. We may not know you or your situation, but we know when you have crossed the line. So since most of us don't carry two guns, then if you carry a bug, sure, it is overkill. It isn't reasonable.
The same discussion can be found for carrying spare magazines. Overkill exists if there is just one spare magazine for some people because they know that the "average" gun fight only requires 3 rounds for a given shooter. As such, anything ammo above that is extra, but since
they are good with carrying a fully loaded gun, then you get to carry more than 3 rounds so long as it is doesn't inolve a spare magazine.
Some folks feel that one magazine is enough, in case your gun has a problem (malfunction) whereby you need a different magazine, not because you actually need the additional ammo. A few feel the additional ammo is good. However, you are engaged in overkill if you carry 2 spare magazines because they only carry one. Since you would be doing more than them and since they are doing what is reasonable, then you carrying two is overkill.
Heaven forbid that you carry a primary gun, spare mags, and a bug. That is just plain crazy talk. You are some sort of mental case.
If you are a LEO, then you can carry more and it not be considered overkill because your life is more precious than the lives of the rest of us.
Now you may try to justify carrying some amount above the norm because you live or work in a dangerous place. If so, then what you are doing is unreasonable and you need to move, quit your job, or otherwise engage in activities that don't put you at risk - unless you are a cop. Because if your life is such that you need to have more than what another gun owner considers is normal and you can justify it by circumstances the other gun owner feels are more dangerous than his/her own, then you are way out of line in your behavior and not all that bright if you continue to engage in it. It just isn't reasonable.
If I am not carrying spare mags, then I carry a bug. My life isn't in circumstances that I consider particularly dangerous. In fact, it is awfully safe. It is just that I have worked out things such that I may carry that much without it being an imposition to me and as such find it prudent to carry what I carry.
Carrying a bug means having a gun as a spare or a gun to share with another should the circumstances require it. Giving a spare magazine to an unarmed person does absolutely no good.