Upvote:5
There is a reference to this distinction in article 3(1) of the directive (my emphasis):
Beneficiaries
This Directive shall apply to all Union citizens who move to or reside in a Member State other than that of which they are a national, and to their family members as defined in point 2 of Article 2 who accompany or join them.
[…]
The rules on border checks, which lanes to use, etc. are defined in the Schengen Borders Code (regulation 2016/399). Instead of “EU citizen”, “EEA citizens”, or “family members”, the Borders Code consistently uses the phrase “persons enjoying the right of free movement under Union law”. It is defined in article 2(5):
‘persons enjoying the right of free movement under Union law’ means:
(a) Union citizens within the meaning of Article 20(1) TFEU, and third-country nationals who are members of the family of a Union citizen exercising his or her right to free movement to whom Directive 2004/38/EC of the European Parliament and of the Council (21) applies;
“to whom Directive 2004/38/EC […] applies” can be read as a reference to article 3 of the directive.
Beyond which lanes you have to use, this distinction also has (arguably bigger) consequences for visa applications. All this is also reflected in plain language advice from the EU Commission.