The reflectors are part of the safety equipment of the bike. An inspection station might catch it or an astute cop even could give a ticket for something like this.
Of course Laws vary and sometimes the cops don't seem to care anyway. A few years ago they had a hard on for youngsters around here that had Blue LED windshield washer nozzles on their hood. They looked sort of cool but the Law here says civilians aren't allowed to use Blue Lights, it was seen as drivers impersonating Law Officers. Several cars got towed and several drivers got tickets and all the Blue Light Washer Nozzles disappeared in several days.
If you were involved in an accident with a car that ran a stop sign in some jurisdictions and didn't have amber reflectors on the front then the other driver would be able to prove "contributory negligence" and may get out of paying you because you didn't have the proper reflectors. Depends on the Laws where the accident happened.
Good Luck with it.