Traction control has been used in AMA for a while now
Seems to me the AMA realized they wouldn't be able to police traction control, so they let it in on their terms. The can identify non-oem sensors, but wheel speed sensors aren't necessary to implement traction control. In fact, an expert recently said that traction control was already being used by the factory teams.
Amar Bazzaz recently gave an interview that was reported over at superbikeplanet.
Basically, Bazzaz told Adams how traction control was being implemented in Superbike (and possibly other classes), but it was either ignored, or someone lacked the mental horsepower to understand what was being said.
The system worked by tracking wheel acceleration (spinning up). Based on what Bazzaz said, superbike teams (and others, I suppose) were monitoring wheel speed (via gear selection/rpm), and when the wheel spun up more quickly than the bike could be accelerated in that gear, the power was cut. There are videos out on the web of a well known superbike team with engines "stuttering" on corner exit.
This allowed the teams to implement a traction control system without using sensors.
So, I'd say "welcoming" is the right word to use.