Your answer is probably dependent on what they want. If they just want to be our friends, well fine (although that would worry me greatly…much could be done under the guise of friendship). What if they demand that we get rid of our nuclear weapons? How about giving up our space travel research? Maybe they want us to follow their religion? Or perhaps they want us to treat animals on Earth in a more respectful way?
The list, of course, is endless, which is always the problem with speculation. It does bring up a point worth considering. What will we do if they make demands? What world body would consider such things? How would the human debate occur to decide whether or not we wanted to accept such conditions?
Humans are a stubborn bunch, so demands may be a mistake on the part of alien visitors. Demands could galvanize a movement that would already exist: the no-go group. The no-go group would exist in any First Contact scenario. They’re the people who don’t want any interaction with aliens, under any circumstances. In most First Contact scenarios, such a group would probably be on the fringe of the global conversation. However, if demands are made of humans, that could change. No-go could be the majority response.
Perhaps visiting aliens would take some time before saying hello, time used to examine the human civilization and develop a decent public relations campaign. For this reason I think it would be highly unlikely that aliens would make such demands. But who knows, public relations is a human concept, they might not give a damn about our feelings or reactions. I suspect though, that if the aliens are seeking to change our behavior in some fashion, they would be very interested in our feelings and reactions.
There’s an easier way to accomplish change on planet Earth. Aliens could simply lead by example. If they are vegetarians, or perhaps won’t eat any plants or animals, they could simply explain how they came to be that way and show the benefits it has brought to their civilization. Then let the humans figure it out for themselves. Sure, it will take longer, but it comes without a threat. And in the end, any offer of help in return for human change is a threat. It’s like high school. If you want people to follow you, just stand around and be cool. Eventually someone will start following. I kind of like the idea of aliens being the aloof, cool kids on the school yard. I bet it would work.
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