Is there any way I can just turn off this functionality? I think it might be because this is an EventsController, and Rails is trying to give me something for free, but I just want to send over whatever I want, especially as I will have situations like an OrdersController, that I want to pass an order to (such as id asc, etc..).
There are 2 things happening. First, by default if the content type is json then rails assumes that the request body (in your case the empty string) is json, and will parse it and add it to params.
The second is something called wrap_parameters.
This wraps the parameters from the body in a hash, so if you posted the document
To a users controller, instead of polluting the top level parameter namespace it would set params[:user] to the result of parsing that.
There is an initializer that turns on wrap parameters. You could remove it and/or only enable it for some controllers.
By default this only happens if the content type is json.
Lastly why are you setting the content type if you're not submitting the request body (if you're trying to control the format of the response I find that it's easiest not to mess around with headers and requests events.json instead)