Many of the folks who run into this problem are visa overstays. Until they get their green cards they cannot leave the country because exiting the country after you overstay your visa triggers a 10-year bar from returning. So they choose to marry here and get their green cards so they can legally enter and exit the country without triggering the bar. That is why they choose to get married without their parents. Even on 90-day fiancee they had to skype one woman's wedding because her parents were denied visas. It happens ALL the time. It is a loophole used by people who violate visa laws. I am all for equal enforcement of the law. My beef is when it comes to the issuing of visas by the consulates and embassies overseas it is done on a disparate basis. Africans, Caribbean folks will get denied for visas being issued freely to Chinese folks who violate visa laws just as much if not more than others. Try and get a student visa as an African and your chances for denial are high even with a college acceptance and proof of finances to pay because the embassy does not believe you will go home after you graduate. But 90% of Chinese students never go back home and they get their visas approved all the time.