If an application is making a request it hasn't marked as being one it is going to make, then chances are, there is a big problem that needs dealt with. In such a situation, crashing as soon as possible means that there's a better chance that all of the relevant data is there to pore through. If you just deny the call, then it could be many hundred of functions later, possibly with relevant data being freed up, and your job of picking through your program's entrails becomes all the more difficult.