Man I miss Beltre. The clip they showed of him running away to the outfield was clearly done in lightheartedness as he left the basepath and it was hysterical. Him and Andrus messing with each other was always a ton of fun to watch. He clearly loved the game but also had a great time which is becoming less common nowadays. Beltre is a legend.
At the time it wasn't, but they've since amended the rules to say that you cannot influence the motion of the ball in any way, which includes blowing on it.
Baseball literally can't function without allowing some cheating, as many unfair practices have been deemed "part of the game" and would be incredibly difficult to enforce.