maximum number of TouchIDs?

I want to track gestures.
So I intend to use TouchIDs to keep track of different IDs.
I plan to use an Array like so:

Code (CSharp):

1. Touch[] touches=new Touch[30];
2.  
3. //setting those touches
4. touches[newtouch.fingerId]=newtouch;
5.  
6. //later access old touches by
7. Touch oldtouch= touches[fingerId];

however this might fail once the touchid is bigger than 30.

to keep performance high I would prefer not to check if fingerId is bigger than 30. However I'm not sure if this is an good idea since theoretically fingerId could be bigger than 30. But how likely is this going to happen?