Question mark usage

Question

Hola,I'm intrigued that the threats are interpreted with a question mark, rather than an exclamation mark. Are they interchangeable?Gracias,

Accepted Answer

Hola a todos
Sorry about the delay in clarifying this doubt.
The use of this structure when it conveys a "threat" (a strong warning) in Spanish generally takes the form of a question. It is obviously a rhetorical question, we don't expect an answer from the person we warn/threaten as it is simply a threat. This in English translates in different ways, depending on the sentence, but generally this would not take the form of a question in English, but an exclamation. 
This is the reason behind those question marks in the Spanish structure and the exclamation marks in the English translation. 
Having said all that, using exclamation marks in Spanish could also be possible, but the intonation that we give in Spanish in this case is more of a question than an exclamation. 
I hope this clarified it.
Saludos
Inma

Answer

The question mark instead of an exclamation point struck me as well. Does someone have an explanation?

Answer

"I bet" rather than "Look out"......you'll fall. Also curious about use of ? rather than ! in warning.

¿A que te caes?" means:(HINT: The situation is: the speaker is watching his child running downstairs)I told you you'd fall!Did you fall down?I bet you'll fall down!I wish you'd fall down!

Answer

I find that a looser translation helps me out here.  "¿A que te caes?" = "What if you fall?" = "You'll fall!!!"