Comment by NewsAware

Assuming attention is binary as parent suggested, than having someone in a meeting where they listen in, but in parallel working on something else seems to me to be a problem. Maybe the meeting should be split in that case so only people who are actually required and therefore spend their full attention on, are present in the split parts. Not saying bossware is the best (or even an acceptable) solution to that problem, but it would surely be benefitial for an organization to reduce such inefficiencies.