Quote Originally Posted by Blatant Beast View Post
This seems to be the whole dispute, in a nutshell. Everyone agrees it is the beginning of the process. The trouble arises in the valuation placed on that.
I'm not quite certain. It is definitely a major sticking point to the dispute, but I don't know it's the entire dispute. Because once you're in, I am still putting forth that Infiltration Expertise makes you belong there, and so you will have a far easier time speaking with the people you're trying to infiltrate and moving around.

It's really the valuation on Disguise/Deception that is on the table in my estimation. Because let's say that your disguise/forgery gets you through the door as a non-assassin. Ok so you're in. Now how far does that get you for the rest of the "mission"? You duped the people standing guard, are you going to dupe everyone else every time? The dice are swingy, which everyone is also glossing over. In my opinion, Infiltration Expertise gets you much further than the door, unless of course you start assuming Read Thoughts and needing to Polymorph into a demon and whatever other obstacles we may uncover in this discussion. At which point these are considerations for everyone.
Some are saying: "Hey, Infiltration Expertise gets you through the door, it is good"
and others are saying: "Hey, Infiltration Expertise gets you through the door, but is that good enough?"
I'm saying it does more than simply get you through the door, but I'm focusing on the door because others are assuming they're just going to waltz in. To my mind, Infiltration Expertise can forego a number of rolls even after getting in through the front. We can completely ignore the door and say a non-assassin doesn't even go for a disguise and forgery and just uses invisibility, climbing, etc to sneak in. And that's fine, it's a different way to do it. But I think doing it with Infiltration Expertise is a fun and powerful way to do it.

With regards to "people are just asking it that is good enough", seems to me like we're just stacking a scenario where infiltration can't be done except by spellcasters. Which means it won't work well in a game that requires the solution to every problem to be spells. I fully admit that.
If having a disguise is all that is needed for entry, then Infiltration Expertise, a Disguise Kit, or a Seeming spell all help enable success, to varying degrees. The Seeming spell is essentially a level equivalent effect to an Assassin's Infiltration Expertise, both are available at 9th level.
Yes, but Seeming doesn't insinuate you into an organization. And Seeming fails to Truesight and Detect Thoughts, which were called out as fail-states for the mundane disguises. I look at it like this:

Seeming:
1. Can be pierced by Truesight (I didn't bring up liches and angels and demons, others did, and they have Truesight)
2. Susceptible to physical interaction (person can feel that the illusion is not there)
3. Allows for Investigation to pierce the illusion (vs Spell DC, so again we're looking at around DC 16)
4. Needs Deception to play the part
5. Needs Forgery to play the part (if documents are involved)

Infiltration Expertise
1. Can't be pierced by Truesight
2. Bypasses the Disguise/Forgery checks
3. Does not rouse suspicion, people simply accept the persona
4. Works over time and can be used over and over again with these same parameters, for long term infiltration and and whatever benefits might come with living multiple lives (Seeming can do this as far as the disguise goes, but has more opportunities to fail)