> It's your own usage only if you're the only user, which is an invalid assumption even before Tor. People aren't shy about sharing wifi with house guests. Tor takes it from "could be any of 25 people" to "could be any of 7 billion people."

> But even regardless of that, why should the expected result of offering a service to the general public put you under suspicion?

Because the police have an obligation to investigate. By mixing personal usage with the Tor traffic, you've muddied the source of the offending traffic, and given them something they can investigate, even if just to remove a suspect. Another way to look at this is should I be able to run a Tor exit node and then expect any criminal traffic seen from that connection, even if from me, should not be investigated? Is the mere presence of a Tor exit node enough to deter the investigation? If so, everyone even considering doing anything illegal should run one.

> If you sell sandwiches you're going to end up with cash that has traces of drugs on it, even if you don't use drugs, because some of your customers or some people they transact with do.

I don't think trace drugs is an equitable substitution. We aren't talking about portscans, we are talking about a higher classification of crime, siuch as child pornography (and I would think crime network tracking, murder evidence, etc). If you're selling sandwhiches out of your house, and spending the cash directly (little or none is going to the bank), and a murder is traced back to you from the cash, yeah, the police might raid you, depending on circumstance. You have a good explanation, but that doesn't prevent you from all suspicion.

> By what criteria do you propose that they distinguish the times they do from the times they don't, which would reasonably put the case in question in the "do the raid" category?

First by police discretion (by whether they try to obtain a warrant), and then by the judge involved. If something needs to change, then it's at this level. If that means the vast majority of the times, the person is not investigated, that's probably not only fine, but right. But I don't think a Tor exit node operator is immediately excluded from all suspicion. For example, investigation of an active terror threat. The reward is so high for active seizure of someone involved, and the possible risk so great for not breaking up the network, that a raid on the exit node operator might be worth it even if the likelihood of them being complicit is very small. Whether other crimes meet that criteria is up for debate, but that's why we have judges to mediate that desire with the rights of the people.

> A large super-majority of individuals work for a business in good standing. Why would they be less likely to destroy evidence at work than at home?

There are more people around, it's harder to hide a crime when other people may have witnessed a part of it, even if they didn't know it at the time. The leaders of the business likely would want to help the police and not the criminal (for many reasons, both selfish and altruistic). If you believed the entire business and all employees were complicit in the crime, or that people with little oversight such as the owner were complicit, then a raid might be warranted in that case as well. A single person working as a business would be equivalent to the entire business being complicit, for the purposes of deciding risk of evidence tampering.

> Would it not make more sense to issue a warrant only if the crime can be tied to the suspect with something more than an IP address known to be shared by multiple people?

Preferably, but I'm more arguing that it should not be a reason they can't. There are simple things people can do to prevent this, such as clearly distinguishing your personal traffic from Tor (such as not running it from your home connection). Providing for ambiguity in the source of criminal behavior will lead to ambiguity in the application of resources to investigate that behavior.