Its a possibility. MLB should be policing/enforcing a set humidity rate but I wouldn’t be surprised if they haven’t been monitoring it. We already know the league is extremely inept.
I have a feeling the whole humidor thing was rolled out in the first place so that MLB can tweak the humidity settings throughout the season and bump offense up or down on command.
The question is, are they even policing the humidor settings in each stadium? Is this the Umpire’s job, or the equipment manager? If its the latter… we already know teams cheat in convoluted ways