“Ask agents to slide the warrant under the door or show it through a window, without opening the door.”
TERRIBLE legal advice. Agents are not required to show you a warrant, just use whatever force necessary to arrest you.
Except for exigent circumstances, consent, or a few other restricted exceptions, the police (including ICE agents) are required to show a judicial warrant before entering a private home.
An administrative warrant (ICE warrant) is not a valid warrant for entering a home without expressed consent.
In public, ICE agents do not need to show a warrant for an arrest.