as a rule of thumb I'd look at the delta - when it nears 100% it is likely you are going to be exercised (I would worry above 90%)
the (19th) Apr IWM is somewhere in the 50's delta. So you wont be exercised unless IWM shoots up quite a bit.
Another way to look at is, is to see how much time value the long side would destroy by exercising the call and how much div. he would gain for that. With IWM at 94.15 and the 94 Call at 1.47 the guy would lose
1.47 - (94.15-94) = 1.32$ in time value and gain only 0.35$ in dividend - no one will do that. Only if time value drops below what you gain as a dividend the option will be exercised. (ignoring financing cost here to keep it simple)