caranthir: @Farkas In most intermediate tsumego in this collection, I think, those that don't require ko for solving have the hint "no ko", so the lack of that statement is effectively a hint that ko is required. You could therefore consider removing the "no ko" hint from those tsumego that have it written.
Farkas: I agree, there shouldn't be hint like this at any Intermediate level tsumego.
b T2, w S1, b Q3 should also be a working solution I think