Id there actually any evidence that that's widespread? I've booked dozens of flights and never once had that happen to me.
A show called Supershoppers did a segment on it. At one point the two presenters searched prices for exactly the same flight, at exactly the same time, one on a Macbook and one on a phone, and the Macbook was more expensive. They also checked the same flight numerous times and saw the prices go up. When using a different PC, they got the original lower price again. They also interviewed an anonymous former online travel agent who confirmed that some websites do this, Trivago being one of the biggest culprits. I'll see if I can find the episode.
EDIT: it was travel agents, not airlines. "Supershoppers S02E03".
