and simply come in peace and showed no aggression and just came to take samples and learn do you think our governments would let them leave or do you think they would try to steal there technology and autopsy them?
I can see us humans doing something that stupid and killing them or imprisoning them,if there is some alien life out there we will probably be classed as a feral planet,which could also explain why nothing as ever visited or at least not recently,there is probably a network of civilizations out there that know of our existence but wont come no where near us,

The aliens would be smart enough to know who is truthful or not and would probably give us what ever technology they didn't think we would wage war with. lol if they came in peace that is

I think the way the human race treats each other and this planet will put off any aliens visiting or wanting to make contact with us, they can probably tell we have had nuclear explosions in the past and would not want to risk us using them against them, IMO.

If we haven't already made contact secretly without the public's knowledge I would rather it be in 10-20 years.
Many people are starting to wake up and hopefully in a decade or two we would be in a better position to handle first contact.
Like you said in the op our leaders would probably try to do something shady, keep it secret, or start a war with them.

You are the alien. They are the earthlings naturally.

"When will the humans leave our planet mommy?"