This was also commonplace in Spain, traditionally. Some people, especially old ones, will say "si Dios quiere" literally every time they refer to any event in the future, even if it's just "see you tomorrow". Not doing so would be considered a "challenge" to God, or Fate, more generally.

Curiously, from "inshallah" Spanish got the word "ojalá", a very common term for expressing hope of something happening (and with no religious or any other "deep" connotation anymore; just like you'd use "I hope").