Why do many LNCS conference proceedings limit their pages to exactly 12 while the guideline says it should be about 12 to 15+?

Question

I found that many conferences strictly limit their submission and camera-ready LNCS page to 12 pages, such as source1, source2, and source3 (without the possibility of extension) whereas some offers extension with an additional fee, such as source4. However, the Springer website recommends 12 pages as the minimum instead of the maximum for a full paper.

My questions are:

1. From the perspective of the conference organizer's side (not the authors of the papers), what are their considerations for this limit, and why are they so strict with it? Is this something like a signed contract from Springer to the particular conference organizers, and they must strictly follow it?

2. What happens if they let some papers exceed the 12-page limit? Is there any penalty from the publisher (Springer)?

Answer 1

Addressing 1: When conference organizers specify the page restrictions, there is an inherent trade-off: More pages means more space for details and explaining ideas thoroughly. However, it also means more effort for the reviewers to read and check everything. Moreover, the page limit is often seen as a default, and some authors might consider the "price" for filling up a certain number of pages too high.

In the case of a conference that has 12 as the upper limit, the organizers probably see this as the sweet spot in this trade-off, maybe based on positive past experiences.

Addressing 2: I have made the experience that Springer is quite open with allowing additional pages. The page numbers of LNCS papers often increase in the copyediting stage anyways (Springer likes to add their own stuff, like LNCS volume numbers etc.). The question is more if the conference organizers are willing to ask Springer for this (which they might not want to do, for whatever reason).