For example, I mentioned in casual conversation with an acquaintance that I planned on performing a ritual with one of my friends from out of town this Samhain. I'm not ashamed of what I am and am very much "out of the broom closet" here at college. This man is an aquaintance, by no means a person who I trust, and a person whose energies had been very off-putting since I met him. Upon mentioning the ritual his reaction was far from appauled, which was unusual, given his beliefs. Then he asked if he could attend (though, not in such a polite way), and when I refused he got defensive and asked me "What goes on in this ritual that you don't want me to see?" To this, I initially thought that he was insinuating that something unseemly would occur at my ritual, which was perhaps his intended meaning. His question does bring up a very valid point in regards to magical practice however.
Last year, coincidentally during Samhain, I was attending a group ritual orchestrated by the Student Pagan Association at the college I was attending. They were a wonderful group of people who I had come to be open about my beliefs and practices with, and I felt safe working with them. That being the first group ritual I had participated in with people I didn't know, I was already apprehensive. When I arrived at the location for the ritual and was chatting with other members of my group one of my friends arrived unexpectedly. He (because it seems to always be a he, doesn't it?) had never been very understanding of me being a witch, even when I tried to take the time to explain things to him and was overall extremely confrontational. Well, he got very confrontational with me while others were setting up the space and I got extremely flustered. He eventually left in a huff because I "failed to show him that I knew what I was talking about". The members of the Pagan Association responded wonderfully and managed to calm me down and help me center before the ritual began. It went very well and was a great experience for my first year of college that I won't soon forget.
After the ritual the president of the group came up to me and said "I really don't understand why you let him push you around that way. It's good he left when he did because there was no way I was about to let him observe our ritual." Between the effect his mere presence had on me and how his actions effected the entire group there was the potential to ruin the entire ritual.
This experience goes to show just how easily a ritual can be thrown off or how a person can be effected by someone who they don't trust. The reactions of the other witches (ever so wise) at the event taught me a valuable lesson: don't let anyone push you around when it comes to a magical practice. This year, I used what I learned, and very simply told this new acquaintance that my ritual is going to be a very personal event and it is my decision who is allowed to attend.
I think privacy is a very important issue in the practice of modern witchcraft, or at least it is to me. There is definitely a place for public rituals if people want to organize them, and I certainly am an advocate of those types of rituals. My point is that privacy is something that you or I, as a magical practitioner have complete personal control over. Being comfortable in the environment while you do spells or rituals is a large part of their success and others don't have the right to intrude. Keep this in mind when you do any ritual, though I suppose it applies most to Sabat and Esbat rituals.
Also, please be courteous to others and respect their wishes if they don't want you to attend one of their rituals!