No amount of OPSEC lectures or packet inspection is going to sufficiently keep the carrier's private information private. There's thousands of sailors on these things. When details like its location and readiness level actually need to be secret, all regular internet access should just be cut off. Radio silence. I assume this person had internet access to use Strava because the carrier isn't yet in some higher level of readiness and its location isn't yet considered much of a secret.

You are correct

Any system that is based on the perfection of humans is doom from the start ..

A jammer is easy and very effective, you can even use it at home to piss off your neighbor, so I guess the army can do it too;