As per Public Health guidelines, neck warmers/buffs/gaiters are not permitted to be worn as face masks, neither are face shields.
As per Public Health Canada ...
Neck gaiters (also known as neck warmers) aren't recommended because they:
Aren't well secured to the head or ears, and are likely to move or slip out of place
are difficult to remove without contaminating yourself
- Public Health Canada
A face shield is not a substitute for wearing a face mask as it does not filter respiratory droplets. A face shield may provide additional protection for the wearer against droplets expelled from another person, however these droplets may still be inhaled around the shield. Respiratory droplets expelled by the wearer may escape around the sides of the face shield, which therefore provides less protection to others. When wearing a face shield, it is recommended to also wear a properly fitted mask.