I wonder if for some reason the direct airport buses were excluded (though I couldn't find any specific mention of them anywhere) or whether the driver did as one of my city bus drivers did and said nothing as people validated their tickets...

Out of curiosity I have emailed the RATP to ask whether what they call "special lines" (Roissybus, Orlybus, Montmartrobus, Balabus) were to be included with the free transports during that period. I'll let you know if I get a response.