Discussing "safety" isn't safe unless you properly define your terms. That is, otherwise, you don't know what type of "safe" people will interpret your words to mean.

(Sorry, tongue got stuck in my cheek.)

Of course, you probably mean type-safety? For example, if you try to add an integer and a string in Python you'll get a TypeError.

Hindley Milner proves that we can infer the most general type of a program. I wonder if your concerns about safety are misplaced, but then I think of languages where one can add 1 and '1' and then I think you've certainly got a point.