halacha - Does casual sex establish a marriage?

• Do premarital sexual relations effect Kiddushin (betrothal/first step of Jewish marriage) if there is no intention of getting married?
  
  
  
  • If so, is the physical act itself determinative of whether or not there is a kinyan (transaction effecting Kiddushin)? (Let's say they would instead be just hugging and kissing: would that effect a kinyan also?)
  
  
  
  
  


• Does the Yichud (seclusion) that the couple is having effect Nisuin? What if there are no kosher witnesses around?