The effectiveness, and moreover the underlying sincerity of these "warnings" have been widely and severely criticized. Meanwhile, the IDF has gone right on bombing people even when they went to areas they were told would be "safe". At the end of the day -- they're just lip service, basically.

Gaza evacuation warnings from IDF contain many errors, BBC finds - https://www.bbc.com/news/world-middle-east-68687749

Israel's warning system and evacuation alerts leave Gaza residents confused - https://www.abc.net.au/news/2023-12-21/israel-gaza-map-block...

They Were Told They Were in a Safe Area. Then Came the Missiles - https://www.nytimes.com/2024/07/15/world/middleeast/israel-h...