Active record dynamic finder symbol gets converted to yaml

When playing with aasm I was trying selectors like:
MyModel.find_all_by_state :active
This returns an empty result while:
MyModel.find_all_by_state 'active'
Returned the expected results.

SQL:
SELECT * FROM "my_models" WHERE ("my_models"."state" = '--- :active')

This is for me unexpected behavior. I tracked the logic back to the file:
activerecord/lib/active_record/connection_adapters/abstract/quoting.rb

I cannot oversee the implications of doing stuff like:
class Symbol; alias to_yaml to_s; end