Again, there are ways to use this technology that does not necessarily involve personalized fares. The airlines already manage fare prices, fare surcharges, blackout/seasonality/applicability dates, and bucket inventory availabilty based on certain high demand holiday periods and events (think CES and Superbowl). This technology can be used within existing frameworks without necessarily generating personalized fares (which will also require additional technology like NDC to be widely deployed). And deploying NDC does not necessarily mean generating personalized fares (see UA's use for continuous pricing). Aside from legality issues, there would be significant reputational issues to consider for any airline attempting to do this.