Tyre creep is a well known phenomenum by us engineers (26 yrs) It is especially apparant on newly fitted tyres. I have always placed creep markers on all tyres which I have fitted to aircraft that I service and found some amazing results doing so. I now work for the large european aircraft manufacturing company and can confirm that all wheel brakes are applied during retraction on all our aircraft. This is done using the aircraft brake system on the main gear and brakes shoe fitted in the roof of the NLG bay, Not only does this reduce the chance of creep but lessens the gyroscopic effects of a spinning wheel in the bay, I recommend application of creep marks but the concern is minimal if using tubeless tyres although it is a good indicator as wheel tyres are carfully placed onto wheels to take account of heavy spots etc and tyre movement can cause severe balance issues.