The most important issues in a First Contact situation will be who is contacting us and why. Those questions lead to many others. Is the extraterrestrial civilization contacting us alone or joined in the contact by other civilizations? If they are alone, are there other civilizations out there in the universe not participating in this First Contact? Why? Who does the First Contact group represent? An entire planet? A federation of planets? Are they representatives of science, government or even corporate explorers?
The answers can help determine how we welcome them and how cautious we must remain. A science expedition would clearly have different goals than a corporate exploration. Perhaps it is a corporate exploration posing as a science expedition. We have certainly done plenty of that here on Earth. Perhaps we are contacted by one political group that has enemies in other groups. Are we aligning ourselves with beings we really want to be aligned with?
This all leads to why: why are they contacting us and what do they want from us? One would hope for a bit of honesty in these revelations, but we should not expect honesty. If we are capable of lying for our own benefit why would an alien civilization not do the same?
This is why First Contact needs to be a careful process. We must put guidelines into effect immediately. We must control all contact and be firm in our demands. This is our planet they are visiting. We are the ones at risk. They can leave and go wherever else they would like. We currently do not have that ability. We may have fearsome weapons here on Earth, but our space technology would most likely be incredibly weak next to a visiting civilization.
There will be a natural inclination to want to believe everything that we are being told. Caution will ask us to dig deeper and move slowly. We could merely be a great location for natural resource mining. Or we could become pawns in some universal political machinations. Or we could be bugs under a microscope for unscrupulous scientists. How do we know these things are possible? We have done all of them ourselves here on Earth and quite often in First Contact situations.
There is a reason why beings expend energy, time and money in exploration. They are hoping for something in return. We can hope that First Contact is a brotherly greeting, but we must plan for any eventuality. And it may not be something we know for some time. We will have to being critical in our questioning and try to see below the surface. They are here for a reason. What is the real answer?