Regarding Proton specifically:
- Proton has been lying about them not logging their users IP and other information in the past. It got caught red-handed in 2021 when they transmitted the data of a user to a french intelligence agency called DGSI. Source(s): https://therecord.media/protonmail-forced-to-collect-an-acti...
- Now they say: "Privacy by default", what they mean by it that by default they do not log the user's information but if an agency asks them to log then they "are required by law" to log the user's data. But the user has no way to know if he is still in the "privacy mode" or has switched to the "surveillance mode".
- It is actually possible that they log everything and use the "by default" wording as a "plausible denial". By saying that your account had been flagged earlier by law enforcement or an intelligence agency.
- All Proton mail traffic goes through Cloudflare. Let that sink in. Yes, they says that the traffic is encrypted using https and that Cloudflare can't see it's content, which might be true. But even if it is true Cloudflare gets to see a ton of interesting meta data, such as the end user's IP, the exact time and the length of what the user is being sending or receiving. Source: So even if you are in Switzerland and you use ProtonMail which is in Switzerland too, your connection still gets tunneled through an American company. Source: https://x.com/andyyen/status/1884907496705339544