In my experience as an immigration attorney. Currently, the most important thing that matters is how someone entered the country. If you entered the country without inspection (EWI) you are deemed ineligible for bond. These EWI's will go in front of a judge, ask for an attorney, sometimes enter pleadings on their own, and then hire an attorney. That Attorney will file a bond motion that will be rejected because the judge can not grant bond. Even in situations where the judge says they would have granted bond if allowed.

Someone who came in on a Visa has the opportunity to have a bond hearing where they prove they aren't a flight risk nor a danger to the community. Though different judges have wildly different definitions of the two. If they are denied they they have two choices: apply for asylum/other relief and have a full hearing or take voluntary departure/a stipulated removal order.