In a recent tweet, a former Democratic ethics adviser had some less than flattering comments for the current president (as is the norm in Washington.) When discussing the investigation, he said,
Kushner, Donnie Jr. and the rest of the Trump crime family better keep their overnight bags handy. Pack shoes with no laces guys.
What does it mean to pack shoes with no laces, and what is the implication here? It must be some colloquial phrase, but exactly what it implies I don't understand.