How visible are the 'symbol of' spells?

[qvcatullus]

Basically, I'm having trouble reconciling two bits of the description, and I'd appreciate someone else's read on it. A forum search didn't help me out, likely because I couldn't come up with fine enough search terms.

According to the 'Symbol of XXX' spell descriptions (they all refer to symbol of death), the symbol must be openly visible:
"Until it is triggered, the symbol of death is inactive (though visible and legible at a distance of 60 feet). To be effective, a symbol of death must always be placed in plain sight and in a prominent location. Covering or hiding the rune renders the symbol of death ineffective, unless a creature removes the covering, in which case the symbol of death works normally."

OK, fine. But towards the end, it says:
"Note: Magic traps such as symbol of death are hard to detect and disable. A rogue (only) can use the Search skill to find a symbol of death and Disable Device to thwart it. The DC in each case is 25 + spell level, or 33 for symbol of death."

If it's openly visible and legible, why does it take a 33 search check to 'find' one? -- that's precisely the verb used. Or perhaps what they mean is that a rogue can identify the squiggle as a 'symbol of' spell -- in which case, if the trigger is looking at or reading the rune, it would seem to me that a search for the rune would trigger it.

Can anyone clear up this apparent discrepancy for me?

[Theli]

Search DC is probably listed for trigger methods other than looking and reading. Before activation, it's likely not obvious what the symbol is, even if its in a prominent and visible location. The search check lets the rogue learn the nature of the rune. The rune may also be disguised besides, and the spell seems to allow the caster to do this to some degree.

If the symbol is made permanent, then you obviously should know where and what it is once it is triggered.