I was amused how PSU was called for OL Holding on their very first series, but Purdue throws the ball 58 times and their OL isn't called for a single holding call.
Now don't get me wrong, the hold called on PSU tackle in first series as Purdue defender attempting to turn corner was absolutely holding under rulebook, but it was ticky-tack compared to what they let Purdue get away with all night long.
A call like this on the very first series can impact the way an O-lineman will play - essentially, it sends the message, "we're watching closely and we'll throw flags if you hold". The diametric opposite message was sent to Purdue - no flags were thrown regardless of what they did including outright tackles of PSU rushers - the message sent to Purdue was, "You can hold with impugnity" and Purdue did.