I've never had a new tyre let go on me, and whilst I don't ride 100% when they are brand new, I don't baby them either.
The only time I have had tyres let go are when the tyre or the road has been contaminated with oil/diesel, one time was when the bike was recovered on a dirty flat bed so the tyres got contaminated and I started riding my R1100RT sideways
My theory, and I could be wrong, is that riders that experience a tyre letting go when new have either a tyre contaminated by the fitters greasy hands or greasy ramp/floor, have hit a patch of contaminated road, or have suffered a 'moment' with the new profile and done something daft.
Accidents would be far more common if all tyres were slippy from new.