Quite. If the selection of letters is due to the ideomoter effect then it should be very easy to demonstrate this. Strangely, however, it has not been demonstrated. I've participated in many sessions - with a wine glass and letters in a circle - and have no idea why sentences come out rather than gibberish. However, it is clear to me that chanting 'ideomoter effect' whenever someone raises this issue is not science but quackery. Only someone who has little experience of doing it could believe this. It is quite easy to rule out this explanation, since it would require that the participants are able to manipulate the glass. This requires the application of pressure on the glass. If you do it with just two people it is very obvious if either of you is applying such pressure. Even if you do it yourself inadvertently the other person will spot it.
On one occasion, just myself and my mother present, the Bishop of Bath and Wells, this was the name the glass spelled out, came on with the message that 'the only way to eternal life is through holy communion'. Some ideomoter effect for two non-Christians. Try spelling out this message on purpose without it being perfectly obvious what you're doing. At the time I thought this message was complete nonsense. However, at the time I thought it referred to the wafer and wine ceremony, and hadn't heard of the communion of the mystics.
On another occasion, for four days in a row, the glass claimed to be James Joyce. A few friends had been 'talking to him' for a while. When I asked to join he told me to **** off, which I felt lent some authenticity to the events. After it/he changed his mind I joined in. Usually the movement is very weak. In this case every now and again the glass would take off round the table at breakneck speed and knock all the letters onto the floor. It was a right pain in the neck continually sorting them out again. We tried many times to recreate this movement intentionally but could not do it. The glass would just tip over when pushed from the top with such vigour.
I make no claims about what is actually happening and do not believe in supernatural occurences. I assume it is a natural phenomenon. However, imho it is about time scientists explained it since it is very easy to replicate experimentally. But all they do is chant 'ideomoter effect', as if that's the end of the matter. But I want to know the answer to this conundrum and will not accept an implausible and unproven guess.