The YAML 1.1 spec explicitly supported unquoted values like "on/off" or "yes/no" as booleans, so the sample below would translate the third element of command to false:

command:
  - redis-server
  - '--appendonly'
  - no

However these boolean representations were dropped in 1.2 as one of the major changes in the spec, in favour of just true or false to represent booleans.

This change is not represented in the go-yaml library, which still supports all previous forms of booleans. I understand it's a claim of the project that it supports most of 1.1 and 1.2, however for larger spec changes like this one, it would be important to have the ability to choose if I want to stick to the 1.2 behavior for booleans, and have the no element in the example above translated to the string "no".