Voted: YES
Reasoning:
I just really like this idea that Petunia is the one to use magic late in life. I think perhaps it will factor into what we find out about her relationship with Lily and what happened when they were younger. I just think it would be a fantastic turn of events to have Petunia, one of the "worst sorts of Muggles imaginable" use magic. Also, JKR has laid a foundation for her in terms of knowing more than a regular Muggle about the wizarding world.
Reasoning:
I just really like this idea that Petunia is the one to use magic late in life. I think perhaps it will factor into what we find out about her relationship with Lily and what happened when they were younger. I just think it would be a fantastic turn of events to have Petunia, one of the "worst sorts of Muggles imaginable" use magic. Also, JKR has laid a foundation for her in terms of knowing more than a regular Muggle about the wizarding world.