The conspiracy theories surrounding the Roswell New Mexico military events have over the years popularized numerous TV shows and movies.
This question must first be answered by asking one. "If there is life on other planets, is it 'sinless' or 'sinful'?" This must first be addressed, as it should be the basis for our understanding this answer. If it's sinful, then did a death on a cross at Calvary some 1,970 years ago serve as the sacrifice for their sins too? If the answer here were "yes", Christ's death was the sacrifice for their sin, then I would postulate that it is possible we earthlings may have such an opportunity, however, since the Bible does not teach this, I'm confident that no such meeting will occur. The Bible doesn't hint that there is life out there so why would we think there is? Does one think God in His infinite wisdom would leave such an event out if it were to ever involve us, His Creation?
I would speculate that we are quarantined because of sin. We have fallen and rebelled against God and are now living under that curse. If there is other life out there, we will be isolated from it because of our potential to contaminate a people's sinless nature.
The people that generally ask me this question tend to be people looking for answers to "why they are here" and they need not look any further than the inspired, inerrant Word of God.