Industry standard LEDs are pretty vibrant, even the budget $40 bikemaster ones are very noticeable in broad daylight. Now the question of whether its illegal or not, well, you can be ticketed for essentially anything on your bike that is not oem. At the end of the day, it comes down on how you carry yourself and whether you act accordingly or not. The police have better things to do with their time, but if you're riding up and down Robson at 12,000rpm you can surely expect to be given a hard time.
Heck I've had a officer come in before while on duty and order a fender eliminator and integrated tail light on separate occasions.
