Some examples in the Player's Handbook are omitted from the SRD's disarm entry
The Player's Handbook on Grabbing Items, in part, says
You can use a disarm action to snatch an item worn by the target (such as a necklace or a pair of goggles).… If the item is poorly secured or otherwise easy to snatch or cut away (such as a loose cloak or a brooch pinned to the front of a tunic), the attacker gets a +4 bonus.… You can’t snatch an item that is well secured, such as a ring or bracelet, unless you have pinned the wearer…. Even then, the defender gains a +4 bonus on his roll to resist the attempt. (155 and emphases mine)
(As mentioned, the SRD omits these examples.) The same examples are used by the Rules Compendium (45). Beyond that, the DM uses those guidelines to determine on a case-by-case basis what gear counts as poorly secured, secured, or well secured.
Also—as you may've noticed—, a worn item can be just secured—that is, neither poorly nor well—, making it so there're actually 3 tiers of security (poorly secured, secured therefore no modifiers, and well secured) not 2 (secured and not secured). Thus the question's chart may need re-examining. For instance, a helmet with a chin strap may be well secured, but a full helmet may be just secured, and an enormous floppy hat is probably poorly secured. Likewise, eyes of the eagle-style lenses would probably be well secured, goggles of night-style goggles would probably be secured, and simple glasses or a monocle would probably be poorly secured. But, again, the DM has the last word on what's poorly secured, just secured, or well secured.