AIS can be turned off. This does raise red flags, but it doesn't seem to stop ships doing it, about 20 million times.[1][2] [1] https://www.wired.co.uk/article

AIS can be turned off. This does raise red flags, but it doesn't seem to stop ships doing it, about 20 million times.[1][2] [1] https://www.wired.co.uk/article/ships-turn-off-tracking-systems-fishing-eu-investigate https://www.wired.co.uk/article/ships-turn-off-tracking-syst... [2] https://usa.oceana.org/publications/reports/avoiding-detection-global-case-studies-possible-ais-avoidance https://usa.oceana.org/publications/reports/avoiding-detecti...