Question or protest a bike at any time, just because its been through the line up doesnt means its got a cloak of protection over it...
the line up is the first pass, and is normally a place to pick the obvious anomaly or class entry issues , but it can be questioned at any time on the line, in the pits, on the finish line, our in a formal protest with Fee for a determination.
If your cheating its a matter of when and hopefully it will get picked up before the places are made offical.