I initially posted an issue when I noticed that by using ParameterFilter (which is used by default, see initializer filter_parameter_logging.rb) I lost indifferent access on the params. I proposed to different ways to tackle the problem:
1) Use ActiveSupport::HashWithIndifferentAccess every time.
2) Use whatever class params is, arguing that filtering shouldn't change the class.
Jon Moss provided some input, which encourage me to submit a PR with the second solution. That way, wether you use the ParameterFilter or not you can expect the result to be the same.