Obviously, being granted a visa to visit a country as a foreign person is a privilege under law; this is totally different from restrictions placed on citizens

Obviously, being granted a visa to visit a country as a foreign person is a privilege under law; this is totally different from restrictions placed on citizens (or persons legally present in the country). This would be terrible if applied to citizens in a LE/IC context. For visas, there are some serious potential negatives to this (it might be used to target those critical of the US Government or specific Presidents, it might be used as a proxy for religion or sexual orientation or some other protected status). It also has positives: aside from catching incredibly stupid terrorists or other undesirable aliens who post a lot of clearly indicative content and then report, it also allows an easy rejection for a person who fails to report a known bad account already connected to him. It's a mistake to assume all terrorists or undesirable aliens have perfect OPSEC. The one corner case where it's probably exceptionally useful is if there's someone like circa-2015 Anjem Choudary who hasn't yet been convicted of a crime, but is recruiting for IS using various social media handles. He's a known individual and more effective as a recruiter due to his public status. He then has to choose either to not report (and thus be banned), to report (and thus be banned), or to delegate US recruiting to someone else (who will be less effective). I'd prefer we collect all this data and then ALSO have a more transparent process for processing visas. It should be clear why one is being rejected, and an opportunity to appeal. There should be reporting of aggregate statistics. The thing I'm most worried about would be a covert policy, of, say, "no redheaded people" which was actually enforced by marking every redhead as an IRA member and rejecting as a terrorist, but that is something which could be addressed. There are probably also explicit policies which people find objectionable and could be addressed through public pressure/voting/etc. (right now I think the ESTA bars for people who visit specific countries might be bad, although I don't know how much worse non-ESTA visa process is if you're from an ESTA country.) USG (and commercial sources) already have increasingly-complete name/passport/etc. to social media identifier and activity databases, so the main point here is to go from xx% to a higher level, and then to set up a "you lied on the form" opportunity for rejection or deportation. On balance, I think this is a good policy change.