OK, so maybe she IS a 'pet' character, if you put it that way. That does not, however, make her a BAD character. The reason that Mary Sues are often so irritating is that they are frequently given more of a spotlight than they actually deserve; they are bad (or mediocre, anyway) characters masquerading as good ones. Silver, as far as I'm concerned, isn't like that. She's smart, she's engaging - I LIKE Silver St, Cloud. Maybe she is a 'pet' character, but she's a well-written pet character created by a good writer, and that makes a good deal of difference.