aykhan wrote:There's no problem as long as you're scalping just roses
What so you mean by light getting into the plastic? As far as I know light will stimulate root growth that's why cuttings are advised to be preferably put in dappled light rather than total shade?
Light getting into the part where roots are formed. Cuttings are placed in light but the roots form underground in the dark. Here, roots will be forming in the air per se, and that area must not receive light!