Others have commented on this. I have received films with the warning but so far have had no difficulty in making a photo copy of an individual Will.
One thought, and I can't check it out until the New Year, is there any difference in where/when the film was made?
From memory, some films were made at the Museum and some at the Rolls Office.
In either case, these are public records and any copyright must surely be with the Manx Government in the same way as the Census copyright is with the UK Crown.
As such there are restrictions on reproducing and publishing the original document, e.g photocopies, but transcriptions, indices, summaries etc. are clearly legal.