Hello,
We process thousands of snipes a day so it is very wasteful for us to check over a thousand snipes every 30 minutes to determine if you have already been outbid. Instead, we check in waves:
If your auction ends within 30 minutes, we may check three times. Within an hour, we check twice. Within 24 hours, probably once. And if your auction is ending in 7 days, we may not check at all.
So while your were not instantly alerted that you were outbid, our system would have notified you in time.
Hope this helps!
Adam R.