I've seen this too often in fell races for it to be funny anymore - eg I lost about 20 places in the Cloud Nine race to the morons who thought it would be ok to trample over a barbed wire fence to skip a stile. (to my shame, I didn't say a word, I just stood in the queue and fumed quietly)
If you want to get through a stile faster, RUN QUICKER.
Next time I see it happen, I'm going to memorise some numbers and get them reported.