There is a kind of light, in my humble experience a 'light of awareness itself' (it seemed to pervade the mind itself, and was not a 'light of the physical world' - twas strange and pleasing, though very fleeting), and in my experience is only perceptible with a still mind, and no thoughts (which isn't something I've had very often, or for very long - just to set the record clear!). While we shouldn't cling to it anymore than anything else, I am not going to push it away either, should it arise again. Interestingly, in my experience, I can only perceive it if I am not seeking it, but rather am very content to just rest with the object of meditation, renouncing all else.
So in my experience, there's not much danger of getting attached to it, because I can't access it if I'm 'wanting' it anyway.
An afterthought: let us not lose our sense of wonder. Let us not try to hose down rapture. It's ok for the process of awakening to involve some thrill, some adventure. Goodness, if with much right effort we manage to let go of sensual desire and the other hindrances for a while, can't we allow ourselves just a bit of bliss? I for one expect awakening to be wonderful - yes, blissful - cos the Blessed One said so!