On the 28th April 2012 I became aware of a new UK Cookie Law that will be in force on the 26th May 2012 and I think earlier in the EU. In reading http://www.ico.gov.uk/for_organisations/privacy_and_electronic_communications/the_guide/cookies.aspx and the associated guidance on http://www.ico.gov.uk/for_organisations/privacy_and_electronic_communications/the_guide/~/media/documents/library/Privacy_and_electronic/Practical_application/guidance_on_the_new_cookies_regulations.ashx I consdier that the cookie used for remembering the state of the toggle is 'strictly necessary' according to page nine of the guidance.
The format creates and stores a cookie 'mdl_cf_topcoll' on the users computer. This is a session cookie (unless changed to a persistent one in 'Remembered Toggle State Instructions' in the Readme.Txt file). The cookie consists of one or more strings of the format 'SiteshortnameCourseid=Data'. The 'Data' is a base 36 encoded 53 bit string to represent the state of the toggles. There are 52 bits, one for each toggle, because of the maximum number of sections that can be defined in the course settings. The 53'rd bit is always '1' so that preceeding '0's are not eleminated in the conversion process. Base 36 encoding is used purely for compression purposes as cookies have limited storage space and use of base 16 'hexidecimal' would be a larger string. I consider that the statement in the guidance 'where such storage or access is strictly necessary for the provision of an information society service requested by the subscriber or user' on page nine applies because each bit is used to set the state of the toggle thus being open or closed. When the user clicks on a toggle, it's state is remembered so that when they return / refresh the course the toggles are as they left them. That's it, they are not transmitted or used for any other purpose. Therefore in 'requesting' to use the course and the format it is 'essential to provide the service requested by the user' and the cookie is not stored until a toggle is clicked upon.
However you may choose to inform your users / legal dept of this as I am not a lawyer.