Avoid spectators to interfere with my EA

 
Hello,

I share a Metatatrader Demo login and password with a third party for demonstration purpose. But how can I avoid spectators to modify orders placed by my EA or to place new orders manually without permission ?
 
only give him investment password .
when you open a acount ,
you received two password,
1st is login for operator,
2nd is for invester not op,
so give him 2nd password is enough