Accroding to The Appropriation Art Coalition applying TPM to public domain content effectively removes that content from the public domain. Is that really true? I don’t think so, and here’s why.

From their post on this subject:

In Bill C-32, there is no ‘expiry date’ on a TPM. A TPM (or digital lock) can, conceivably last forever, this means that works will remain inaccessible even after they enter the Public Domain. Furthermore a digital lock can be applied to a work already in the Public Domain. This effectively removes the work from the Public Domain. This means that the legislation in Bill C32 opens up the potential to decimate the Public Domain

But let’s see what bill C32 has to say about this:

“technological protection measure” « mesure technique de protection » “technological protection measure” means any effective technology, device or component that, in the ordinary course of its operation, (a) controls access to a work, to a performer’s performance fixed in a sound recording or to a sound recording and whose use is authorized by the copyright owner; or (b) restricts the doing — with respect to a work, to a performer’s performance fixed in a sound recording or to a sound recording — of any act referred to in section 3, 15 or 18 and any act for which remuneration is payable under section 19.

Now, as the copyright holder is either dead or has waived his/her rights, what was previously a TPM - or could have been one, no longer falls within the definition and can now legally be removed.