Invisible Traps and Meta Magic items

[Hima Flametinker III]

So, without spoiling anything, I ran a game where PC's had encountered an invisible trap. As written, it says "Visible only via use of Detect Magic, See Invisibility or other similar effects." So that brings me to my question. If lets say 3 of the 5 PC's who can see it with magic and are telling their "trap finder"/disable device-er to disarm the magic trap. How does that even work?

Next question:
When using an item that grants the effect of a MM feat. Must one still expend additional spell slots as described or does the limited use of Rods or X/day counter that?

[Undone]

those with trapfinder CAN by RAW find it. The trap is just base DC +40 for invis.

[Cevah]

The magic of the rod specifically provides for the extra oomph of the feat. Note the cost for a +1 level effect is cheaper than for a +4 effect.

/cevah

[Pizza Lord]

For trying to disarm a trap whose components you couldn't see, I would apply the -4 penalty to Strength- or Dexterity-based checks as per being blinded in this case.

Obviously, being totally blind as opposed to 'unable to see something specifically' isn't the same thing, but I think the procedure applies a reasonable guideline.

[Cevah]

I would not apply the blind effect, since lock picking is a "touch" skill, by all accounts. You may need to take longer to locate stuff, but the "feel" is how you disable it.

One caveat is that finding the trap may in fact trigger it.

/cevah

[Pizza Lord]

Don't try and shift the thread discussion. No one is talking about opening locks, we're talking about disarming traps. The two actions may use the same skill but they do not (necessarily) apply the same methods and activities. Just like Acrobatics covers jumping, tumbling, or balancing that doesn't mean something that affects one affects them all.

If you're seriously saying that it's just as easy to cut the red wire instead of the blue, green, yellow, black, or white wire when disarming a trap I will disagree.

If you're saying it's just as easy to reach into a hole trapped with poison needles and not accidentally prick your finger when you can't see what you're doing I will say you are wrong. Sorry, I think a -4 for Dex-based skill checks for not being able to see, as per the rules for not being able to see, seems like a fair ruling.

You don't have to agree with me, but I can't in good conscious see the validity in your statement as it pertains to the question. You can say that walking a tightrope is 'touch' based but, I will still apply a penalty if the rope was invisible or you were blind (in addition to movement penalties for being blind). It's still doable, but it isn't as easy to do.

[Tarantula]

I'm assuming this is a mechanical trap that had permanent invisibility on it. I agree that the -4 penalty from Blinded could apply to the disable check on the trap. Seems reasonable to me.

Otherwise, I'd say the AP should have specified what penalties are in place for it being invisible, since that is a non-standard trap effect. I would probably rule that without a way to see the trap, attempting to disable it would be very likely to set it off. I would represent this by if they fail the check at all, it would set the trap off, and I would apply the -4 penalty from blinded to the check.

[wraithstrike]

I would have just glittereddusted the trap or used dispel magic.

The adventure in question should have given more rules, as Tarantula mentioned, since there is nothing official on this.

[shroudb]

I always find it a bit stupid that NPC wizards with int up to 16+ go into all the trouble to make a trap invisible but fail to cast a simple magic aura on it...

PCs will be walking with detect magic active, and intelligent creatures know that. But why oh why cast a 1st level spell to hide your magical grasp for DAYS?