Backup Question.

[Hercules24]

Everytime I make a backup using PHPMyAdmin I do it like described in http://coppermine-gallery.net/demo/cpg14x/docs/faq.htm#BackupDatabase
However CPG says: DON'T check "Add 'drop table'" - your database will be erased, if you do.
I have always checked the "add drop table" when I saved the backup sql file to my HD, but my dbase was never erased.
Isn't the "add drop table" only used when you reinstall a backup over a current SQL dbase so it clears the old stuff and only installs the data you backuped?
Without checking "add drop table" me thinks you get everything double when trying to use a backup.
What Am I thinking wrong?