Stephen Hawking talks about how we should hide from aliens:
I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach. … If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the Native Americans.
At least until we get our own massive ships after looting the Earth for goodies and go out on the prowl.
This is the plot for “The War of the Worlds” after all. Just the distances may be many orders of magnitude greater.