But, no, I would buy a tool that fits my purpose. If my purpose is to hit a baseball, or hammer in a nail, I'd buy a real bat, or a real hammer, because that's the purpose of the tool.
If my goal was to swing it at a friend, though, I'd probably go for the foam bat. Just like, if my purpose was to build a piece of software to archive emails, I would build it so as that it is clearly its purpose, and it would be engineered in a way to make it challenging if not impossible to be used to secretly abscond with someone else's conversations.
You seem to be interpreting my response as "people shouldn't build tools that can be used for dangerous purposes", when instead I am saying, "you should understand, and take steps to ensure, that the tools you create are used for their intended purpose." Hopefully that purpose isn't spying on people, but if it is, be up-front about it!
... Thereby ensuring that it is more difficult or inconvenient for legitimate users (access prompts and notifications are cheap, not free). It's a potentially legitimate tradeoff, but it is a trade; the question is whether it's closer to enforcing sane password requirements online (probably necessary), or aliasing rm to rm -i (helpful right up until you actually need to delete 300 files at once).
As for "age-restriction" labels, they are merely at the parents' discretion. I don't think a toy store would ask for ID and refuse a sell if age indications were not met.
I want my tools to be sharp, pointy, and effective.
Blunt your own tools, but don't tell me what I can do with mine, please.