This is a good question. I've answered many almost identical questions to this one before, so I'll only give a brief recap here.

Ghost Hunting (GH) is in no way a true "science". There are some scientists who engage in this activity, but it is (as you suggest) a sort of hobby - an none of these claim that ghost hunting is genuinely a science. Science requires the use of the scientific method, which demands that any data collected be reproducible. This is one area where GH fails the test--one cannot reproduce "ghost data".

Further, there are no scientific thoeries that make testable predictions wrt ghosts. Period. GH is what we refer to as a "pseudo-science" -- that is, something that is NOT science, but is presented as if it were. Sadly, there is no law to forbid this, so it up to you to know the difference. One thing to look for with pseudo-science is if it's being used to stir up public interest that can lead to income for the presenters; or if it's being presented as enteratinment--like "TAPS".

Really, be careful with this. One can legally call anything "science", no matter how un-scientific, or totally lame it is. Be sure you have solid definitions of: Science, Theory, Hypothesis, and the Scientific Method. Knowing these well will help you not to be fooled.

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