This isn't surprising but there were copies of Children of Hurin being sold on e-bay today, which Christopher Tolkien and Alan Lee had purportedly signed. One look at the signatures will tell you that they were definitely
fake.. There were an even larger number of bogus bookplates "signed" by Lee and Christopher Tolkien offered for purchase (totally separate from any book).
For a rather humorous but sad discussion of these type of forgeries, which seem to be more commonplace every day, see this thread on a collecting website:
here. A number of the posters on this forum are book dealers.
The family and estate has to hate this kind of thing.