While I applaud the wizard's chutzpah...

The Accidental Activation Rule Is Terrible

I fully agree with KRyan and Ernir that ignoring the accidental activation text is the best way to go. It causes more problems than it solves. I'm of the opinion that it's included only so the DM can have hilarious situations occur at the tavern because the wizard forgot the command word for his wand of fireballs was hubba hubba.

But If You Must Use It...

If you're dead-set against totally house-ruling it away, here's one way to run it.

The command word text reads, in part,

A command word can be a real word, but when this is the case, the holder of the item runs the risk of activating the item accidentally by speaking the word in normal conversation. More often, the command word is some nonsensical word, or a word or phrase from an ancient language. Activating a command word magic item is a standard action and does not provoke attacks of opportunity.

Emphasis mine. Not possessor, by the way. The holder specifically--as in what one does with a hand.

The description of the pearl of power reads, in part,

This seemingly normal pearl of average size and luster is a potent aid to all spellcasters who prepare spells (clerics, druids, rangers, paladins, and wizards). Once per day on command, a pearl of power enables the possessor to recall any one spell that she had prepared and then cast that day. The spell is then prepared again, just as if it had not been cast. The spell must be of a particular level, depending on the pearl. Different pearls exist for recalling one spell per day of each level from 1st through 9th and for the recall of two spells per day (each of a different level, 6th or lower).

The wizard can create multiple pearls of power all with the same command word. The wizard can activate one pearl of power in the wizard's possession as a standard action using that command word. If the wizard holds in her hands two or more pearls of power when the command word is spoken as a standard action to activate a magic item, one of the pearls of power in wizard's hands activates, determined at random.

(This assumes that the DM determines that a held magic item takes precedence over a merely possessed one with the same command word and that the DM wants to stick to the (actually far more important) rule that activating a command word magic item takes a standard action, and therefore simultaneous magic item activation can't happen accidentally, much less, like here, as some kind of faux accident. I went with random determination as that makes sense if multiple pearls with the same command word are deliberately held and the holder fails to specify which one to activate when the command word is spoken.)

So here's the thing - the spells used to create a magic item do not have to be identical to the effects of the item. A Cackling Hag's Blouse requires hideous laughter, but the effects of the blouse have nothing to do with the effects of that spell, it's more of an implementation of sympathetic magic. You have a lot of wiggle room and as the GM, with your game-designer hat on you can basically can make magic items that do whatever you want, and just pick a metaphorically and power-level appropriate set of prereqs.

As a result, if you want a ring that's going to do some rope of climbing/animate rope combo, just make it. (Note that the spell requires to make a rope of climbing in the first place is animate rope.) Add some other spell requirement and cost it up from a normal rope of climbing. I might call it "Ring of Spiderman, Requirements minor creation, animate rope, list price 8000 gp."