The only negative effect I see of these record attempts is that it will increase the numbers on and around the trail.
(and continue to upset those looking for the "wilderness experience") (which is already somewhat of a rarity on the AT)
Lots of other trails out there.
The movies are even more guilty.
Wait. It's going to get worse.
Speed hikers will be the least of your worries.
Soon to come: daily limits (like the PCT now has), lotteries, fees, more fees, more ridge runners, charging stations, more crime, maybe even hot dog and coke stands at the road crossings. (for profit). and lastly (and the worst to me): More Rules!