In practice, pretty low! In the vast majority of cases, people are released within a few hours and not sent to one of the larger detention facilities. As much as the news sensationalizes the handful of cases where that doesn't happen, the likelihood is still quite low that I wouldn't get due process.

If I saw an ICE operation in my neighborhood, I wouldn't be too worried about going up to them and demanding their name and badge number. I'm not going to be "disappeared" or anything like that, especially as a US citizen. The vast majority of those targeted are actually illegal immigrants, and the extras arrested are often obstructing justice in one way or another. If I approach it completely legally, I don't think I'd be falsely accused of something else by those officers.

Don't get me wrong, I am 100% against what ICE is doing. I think they're being a bit too fast and loose with their information, such that they arrest or detain far too many people without actual cause, and those they do arrest with cause they mistreat. I'm not necessarily against illegal immigrants getting deported, but that should be handled with respect and restraint, at least until we get policy to get these good people on some form of temporary status. If someone currently has work here, there should be a really easy way to get that turned into a legal work visa.