I have been stopped exiting the business check-in section more than once.... given, not as many times as I was stopped just rushing to security though the economy section as i already had my mobile boarding pass.

VIE is one of the nastiest airports out there in regards to enforced carry-on dimensions.

But once inside the secure airside gate area, never was approached. Tag on the bag or not. Just a few times the gate agent walked around the gate area and asked people to gate check rollers or big bags since the flight was very full. But even there, was never a problem to say "No". Simple solution is not to crowed the gate area and just walk up to the gate whenever boarding really starts. Then they will not care anymore.