As you pointed out, its legality depends on interpretation of "can do so safely". If the choice is between getting hard on the brakes or entering an intersection on amber, I do the same thing as sempel: speed up to clear the intersection sooner. In all my life I have never had to enter an intersection on a red following this strategy, but plenty of times the light has gone red before I have exited the intersection. Unless the intersection is massive, in which case the length of the amber should be longer, this doesn't pose a risk.It is not legal according to the Highway Traffic Act 144(15):
Amber light
(15) Every driver approaching a traffic control signal showing a circular amber indication and facing the indication shall stop his or her vehicle if he or she can do so safely, otherwise he or she may proceed with caution. R.S.O. 1990, c. H.8, s. 144 (15). [my emphasis]
As long as red light cameras are catching people entering an intersection on red, and not those already present in the intersection when it goes red, I'm fine with them.