Why of course you can't know who visits the president. It's only the most public figure in your country, drawing his salary from tax dollars, living in a tax-dollar funded mansion and voted into office by you. Of course the president knows everything about you, what emails you get and send, whom you talk to over the phone, what you're talking about and who you send text messages, and you're paying him for the priviledge to have no privacy whatsoever to the tune of nearly 25% of your income a year.
What, you thought that'd ensure he's working for you? Oh you poor poor deluded soul.