Probably wouldnt bother me - my forthcoming wedding is not about the wedding but about the marriage.
However, I see two issues. One, is in my experience, crematoria are often very very busy. And let's face it, you can't "plan" for death in the same way that you can a wedding. If someone dies, the corpse has to be disposed of within a reasonable amount of time.
Secondly, how are grieving relatives going to feel when a happy couple and their guests roll out of the hall looking all happy and cheerful when they are about to conduct a service for a loved one?