Protection or not ?
Asenath:
Not sure exactly which point you want clarification on, so I will try all of them!
A Tarot deck, like a ouija board is an inanimate object. They are nothing unto themselves, merely tools. A drill is a tool; you use it to drill a hole in wood, which is a good thing. You can also drill into a skull with it. A neurosurgeon using it in this manner is a good thing; to torture and kill someone by drilling into their skull is not.
Merely having a tarot deck or a ouija board in your home is not going to put up a beacon for all nasty spirits out there to 'zero in' on your house.
Beacuse of the reputation that ouija boards have, many innocent people, usually teens, buy one and decide that whatever they saw last week in some movie is 'the way to do it' and call up all sorts of stuff they don't know is real or not to 'make' their ouija board work. Opening a door? Yes, inexperienced people can unwittingly call up ANYTHING that happens to hear the call, whether you 'believe' in such things or not. Getting rid of something unwanted is not the job of amateurs.
On the other hand, many people involved in occult dealings are aware of protection spells and other 'ritual' things such as casting circles, calling watch towers, etc. These are done to make a wall to 'keep things out.' They really do, but in the casting to keep things out, sometimes 'things' are inevitably drawn to the energy present. This is why once you cast a circle you have to remove the circle (in most cases). However, you also have to cleanse the area to lingering energy on which unwanted spirits or other energy are attracted to and can feed on. Unwanted energy may not hurt you while within your protected area, but unless you send them away ... they may stay.
I am not saying you or your friend has done any of these things. However, ouija boards fall into the influence of a spirit realm, whereas tarot cards do not. To call on spirits to 'do your bidding', even with inoccuous things such as trying to reach your dead grandmother, can be dangerous and disasterous in the hands of an inexperienced practitioner. You may be interested in a biography titled "Familiar Spirits" written by Alison Laurie about her two friends David and Jimmy, who consulted a ouija board every night for almost four years, and the effects it may have had on their lives, relationships, and professional lives.
I hope this answers your question about protective measures. There are threads on protective circles, I believe, on Aeclectic under 'The Lesser Banishing Ritual of the Pentagram' and 'The Rose Cross'. Neither of them is exclusively affilliated with a particular belief system and can be used by anyone.