That would mean they would have to be with in 5 light years or less of us to make such a journey. If they were indeed that close their civilization would be emitting massive electro magnatic radiation in the form of radio waves, microwave and everyother wave in the spectrum. If that were so we would HEAR them before we could see them. At this moment our planet is flooding the local universe with our electro magnatic radiation. Any civilization within ear shot would know we exist and where to look for us.
Your premise of having to be 5 light years or less may be faulty based on our primitive understanding of quantum physics and science.
As far as any civilization within earshot would know we exist and where to look for us.
#1 Perhaps they do and are here and conduct experiments with us and deal with the less primitive of us. There are many accounts on the internet of this being the case.
#2 An advance civilization would view us as very barbaric, primitive and dangerous.
#3 just like a cow, pig, sheep, doesnt know why it is here,(to be consumed) perhaps we are being raised and harvested, (our invisable souls) by beings from beyond.
Just something to think about.