Why are New Orleans cop cars parked in Houston?

"A number" of New Orleans cop cars have been seen in Houston lately, "several" of them stored in Houston Police Department parking lots, the Chronicle reports.
Exactly how they got there remains shrouded in mystery as well as perhaps cowardice and corruption, although the last two can't be confirmed. HPD was told not to arrest the drivers.
Yes, but why are the cars there?
"That was the only mode of transportation," [Lt. Robert Manzo, an HPD spokesman] said. New Orleans police officials "are not interested in pursuing any charges against (the drivers.)"
I'm sure each of those police cars was loaded with refugees.
However, for the other side of the story, see "A Home for the Brave" about some NOPD cops who stayed behind.