I am into recruitment and to be honest with YOU, I don't think any employer will allow his employee to go home at his own will at anytime he/she pleases unless of course you hold a senior level position. However, during the salary negotiation you should bring this case to the HR and should be stated in the contract so that it becomes your right and not just a privilege.

Probationary is between 3 to six months, during this period any party can terminate the contract subject to terms and conditions stipulated in the employment contract.