check my evil plan: avatars

[bulbasnore]

So, hypothetically, let's say its April 1.

1. select userid,avatarid from user order by userid; (then save that as a file)
2. back up the customavatar table
3. update user set avatarid = 1337; (now everyone has the same avatar)
4. *time passes: morning and evening, one day*
5. use the list of avatarids from step 1 to update the avatarid field as per the value of each user (now everyone has the same avatarid value as they started with)
6. restore the customavatar table (now those who have the rights to customavatar upload have the original avatar)

Is there any maintenance I need to do after this?
Is there something I'm not accounting for in vBulletin that will prevent me from putting everything back as it was?
Any indexes or whatever to rebuild?

Thanks... I promise not to reveal anyone who helps me to my users! And, of course, you bear no responsibility if I blow the whole thing up!