I find the common procedure of key signing parties a little awkward:
Person A presents the passport and a fingerprint "This is my key!". Person B checks the passports and decides a level of trust to sign the key at home.
Now the only thing person B can really confirm is that person A was present (based on trusting the passport) claiming that the printed key is his/hers. The only mapping to the key is by name though - which might not even be unique.
In fact person A could have looked up someone that has the same name and payed him/her to go to that key signing instead. Unless the key has a photo id (very few have) no one would notice. Maybe not very likely or even an attack vector but an example to show the problem.
The only way to confirm that person A has access to the private key is for her/him to sign something. Yet signing (or even just bringing keys) is usually not permitted/wanted on most key signing events.
But wouldn't that make much more sense? No trust delegation to a passport. No visual matching to a photo. What am I missing?
Would you consider the common procedure more secure than signing on the spot? Can you imagine a better alternative to the common procedure?