>This is why I'm strongly against spam filtering for email. Spam filters are fundamentally security-through-obscurity. I mean, they don't protect your email from targeted bombing attacks or phishing. If you need spam filters to operate your email on a day-to-day basis, then the security of your email is fundamentally broken.

You kid, but this is completely true Email is simply an incredibly flawed, outdated and broken system, especially when used without PGP. Phishing is a massive problem, and it has only continued to grow in scale because spam, uh... finds a way. At the same time, spam filters regularly create false positives, making email an unreliable transport (leading "oops, it got lost in my spam folder").

>Blocking Tor isn't a security measure, it's a nuisance reduction measure.

You should block all IP space, this will reduce nuisances by 100%. In fact, this will save you from having to consider any real security practices or do your job properly.