εxodus has found at least 5 games embedding Alphonso tracker: https://reports.exodus-privacy.eu.org/trackers/82/
"Alphonso listens to audio signals in TV advertisements and is included in games and other apps for children."
I'm fairly sure this tactic may contravene domestic laws in at several EU countries (especially targeting kids and embedding the sound in TV ads)
With DVB-T(2) its unclear what actual audio bandwidth of linear TV is but likely to be 20 KHz max. Putting near inaudible high frequencies into the adverts is potentially also a source of annoyance/distress to the children (esp babies) and pets (such noise was used to scare away teenagers from outside buildings in the UK!)
TBH each EU country has its own domestic laws that take precedence, but I think this is something that Communications Ministries/media regulators (i.e Ofcom UK and equivalents elsewhere should be made aware of, as in many countries it is already illegal to target children for advertising certain products such as junkfood and the marketers tend to do stuff like this to try and get around these regulations.
Alphonso partners: http://alphonso.tv/partners/
Experian, Acxiom and LiveRamp are 3 big data-brokers. Cf. https://esther.codes/content/images/2017/12/Screenshot-from-2017-12-30-00-50-54.png
@exodus @U039b I no longer watch linear TV (for kids or adults) and don't play computer games, but this should be fairly easy to test by converting the audio output of a TV broadcast to a digital recording and using the spectrogram display modes (I think even Audacity has them) to investigate any unusual content in the higher frequency bands.
I think there is a French law about "peak loudness" on TV audio as well; which may also impact on the legality of using these techniques!