ACARS messages, like ATC instructions, have to pass through a couple of discriminatory and rather discerning individuals - the pilots. A spoof sender will also have to spoof the message acknowledgment/receipt. Also, the moment a duff message is spotted the game is over. I just hope they don't find out that you can spoof ATC messages with radio. That would be groundbreaking research and surely worthy of another press release.
And this is yet another example of EASA (pronounced E-Arse-A) pointlessly wasting our money. These plonkers are p!ssing away our cash on so called experts like this to tell us what we already know. Then they have the gall to release this worthless and totally pointless research to tell us what we already know. Next they'll work out that if our engines stop it might mean we won't get to our destination.
PM