This week, U.S. Immigration and Customs Enforcement (ICE) released new guidance on "facility visit and engagement protocol for Members of Congress and staff."
"ICE detention locations and Field Offices are secure facilities. As such, all visitors are required to comply with [identity] verification and security screening requirements prior to entry," it specified. "When planning to visit an ICE facility, ICE asks requests to be submitted at least 72 hours in advance."
Incidentally, it's perfectly legal for members of Congress to visit ICE detention facilities, even unannounced. And ICE's attempt to circumvent that requirement threatens the constitutional system of checks and balances.