roybatty,
Your mother's story seems one to be repeated by many individuals. Not denying that it happened. I find that most of these experiences are positive (not that they are not scary) and in many individuals they claim it was a sign to get them through what ever it is that they were going through. There are of course those who have very negative experiences which they would soon rather forget.
Most people who write on this subject agree that one must be looking for these spirits, esp. deceased family members, in order to make contact. They normally do not appear out of nowhere. I served for years as JW elder and can only recall one or two exp. that dealt with the super natural, but they were personal friends of mine so I can attest to the validity of their claims. Needless to say that both these experiences were very negative, and what is worst they were real. Why they don't appear in the Super Bowl and scare people? I don't fully know the answer to that question, and to be perfectly honest, I am glad they don't, perhaps they are governed by a higher power, a source if you will, and have certain parameters that they are forced to adhere to. But like I mentioned earlier many of the exp. that I am referring to deal more in a positive nature.
Now that I am no longer a JW I am doing a more comprehensive study into this subject. By no means an expert but some of the stuff would blow you away. I do not believe in Satan or the concept of sin hence the need for sacrafice. I do believe in good and evil and the constant struggle that exist between the two. No one is forced to be evil, one chooses it. We are accountable for our actions. Accountable to whom? Many call him God, others Creator, others Goddess, whatever you choose to call it it exist. It is a law of the universe. I agree with you wholeheartedly, it is better to choose to do good...... just in case.....