Maybe they weren’t warnings. Maybe they were “imprimaturs”.
Websters says for imprimatur ...
... a mark of approval or distinction.
... sort of like those political commercials where the candidate says, “I approve this!” (or “I sanctioned this.”).
Gen 1:14 And Elohim said, “Let lights come to be in the expanse of the heavens to separate the day from the night, and let them be for signs and appointed times, and for days and years, 15 and let them be for lights in the expanse of the heavens to give light on the earth.” And it came to be so.
sign: a signal, flag, beacon, omen; (properly in relation to time, to come, of the future)
God gives His approval or disapproval via blessings and curses. He never says I give you a sign as My approval.