Enabling checksums on a streaming replica

I'm wondering about the validity of using the pg_checksums utility to
enable checksum's on a streaming replication standby, and then promoting
that standby as a way to enable checksums on existing clusters.

I've tested the process out, and it "works" (by works I mean doesn't blow
up or log any errors). But this seems far enough outside of supported
territory that I'm curious what others think.

The process is:

- Primary with checksums off
- create a streaming replica off that primary
- stop the secondary
- enable checksums on the secondary with the pg_checksums utility
- start the replica
- promote the replica

I've thrown load at it while the it was replicating from checksums off ->
checksums on, promoted it, and verified the checksums after with
pg_checksums.

Any thoughts on this approach?

Thanks,
Brad