I can see bringing your laptop bag with you everywhere, just to be on the safe side. It is company policy for me. Even if the odds are almost 0, I still take mine with me . If it were lost/stolen/misplaced on my watch, especially as that means I ignored protocol, I'd be fired pretty quick. In fact, I refuse to carry it whenever possible because of that hassle.

As far as a suitcase - no idea there. It always has the potential to be checked at the gate anyway, so prudence would say never pack valuables in there.