Infamously the 2nd edition of the otherwise excellent Warhammer Fantasy Role-Play tried this.I'm very glad that it's stated somewhere within the rules that sources of light can be seen much further away than they shed light. This is basic common sense, but from personal experience, some people out there have no idea how light functions.
That the light from a lantern stops when you reach the radius where you, the lantern-bearer, no longer gain any benefit is sheer and utter lunacy.
There's a reason WWII soldiers cup their hand when lighting a cigarette.
And that reason is that even the tiny light from a match can travel a mile away.
Anyone playing the game in such a way monsters aren't alerted far in advance when the classic adventuring party (with members needing light) clambers around dark caverns or outside at night just reveals their ignorance.