It uses your settings to determine what type of box should be shown. Since unregistered users have no settings, it will use the default editor (should be the same with guests posting threads and such in
vB).
If you look in your ecard.php file though for this code:
Code:
Content visible to verified customers only.
And add this right below it:
Code:
Content visible to verified customers only.
Then that should enable the WYSIWYG editor for guests.