Apparently you can't do anything at all once you sign a contract with the Cubs.
Take, for example, section C(2) of the Cubs' guarantee language. It says the Cubs may convert a player's contract "If Player is injured in any Prohibited Activity."
The prohibited activities are as follows:
"(A)uto racing, motorcycling, piloting, co-piloting, learning to operate, or serving as a crew member of, an aircraft, being a passenger in a single engine airplane or private plane, hot air ballooning, parachuting, skydiving, hang gliding, bungee jumping, horseback riding, horse racing, harness racing, fencing, boxing, wrestling, karate, judo, jujitsu, any other form of martial arts activity, use of an All Terrain Vehicle (‘ATV'), skiing (water or snow), snowmobiling, bobsledding, luging, ice hockey, ice boating, field hockey, squash, spelunking, basketball, football, softball, white water canoeing or rafting, kayaking, jai-alai, lacrosse, soccer, tennis, rodeo, bicycle racing, motor boat racing, polo, rugby, rodeo, handball, volleyball, in-line or other roller skating, surfing, hunting, paddleball, racquetball, archery, wood chopping, mountain climbing, boating, any weightlifting not prescribed by or approved in advance by Club (said approval not to be unreasonably withheld), participation in the ‘Superteams' or ‘Superstars' activities (or any like activity) or other made-for-television or made-for-motion picture athletic competitions, or any other sport, activity, or negligent act involving a reasonably foreseeable substantial risk of personal injury or death."
Jesus. Can they even masturbate?