If the disease does not ever manifest itself in any way whatsoever, then that disease doesn't exist. Such a disease exists; so it must have symptoms. Perhaps there is no quick test that you can do to find out if the animal is infected. But it only means that the animal stays in the shelter until the answer becomes known. The only way to contract the disease is to eat the deer, and I don't think that it's very likely at the shelter.
Legally, the LEOs could have been correct, and transportation of a wild animal without proper paperwork is prohibited at least in this state (CA.) But going around and shooting Bambies is not how you should spread love. The deer did not know what hit him. It's the people who were hurt. Humans do not hunt fawns for a reason. Traditional hunting societies respect life; they only take a grown animal, and only when necessary. Humans of all societies are reluctant to hurt the young.
All the prion diseases listed have long incubation periods, but you knew that didn’t you?
All the diseases listed have frank, overt, and horrific symptoms in their advanced stages, but you knew that too, didn’t you?
I assume you also know that Chronic Wasting Disease in deer is spread from deer to deer, I also assume you know that deer don’t customarily eat each other. They do doo-doo and deer doo do contain enough prions to contaminate feed and fields.
But by all means don’t let that stop you from advocating moving deer from contaminated areas to clean ones. California could use its own outbreak, that would certainly serve those eeeeeeevil hunters right for *sob* shooting BAMBI’S MOTHER!!!! BooHooHooHoo!!!