The bip91 has been locked in. However, miners still need to come to a concensus on the HF part. After SW is activated, there's nothing to prevent the miners switching back to core version with signal 1. Only around 80% signed NYA and nobody knows whether anyone will quit.

Keep monitoring signal 4 may help to check who switched back to core version, but after SW is activated false signal 4 needs only a trivial patch on core version.