Anyone can be arrested. Police can, and do, make mistakes. Being arrested does not make you a criminal, you are a criminal when you are convicted by a jury of your peers.
If you crossed the border without proper authorization you committed a crime. You are a criminal. It does not take a trial to prove that (and I do not believe illegal aliens get a trial, there may be a hearing but not a trial).
“A jury of your peers”. That only applies to bona fide citizens. Unless we want to start swearing-in illegals to act as jurors for other illegals. It’s fundamental. Those here illegally only have one right; the right to get the bleep out of our Country.
Illegal aliens are already breaking the law simply by being here, being arrested for anything else simply adds to it.