Do I really need Session Replication?

I am working on a number of web projects for a firm. Most of the projects are about one or two pages of input and then doing a save to a mysql database. Very Basic projects. My SA's are pushing to try to get session replication working in JBoss but I don't really see any need for it and all of its overhead.

We need load balancing and clustering so if the server does go down we can move the new requests to the backup service but I am not to big in session replication.

This is very low volume projects. In my eyes what is the odds of a user being in the project as the server goes down on the one or two pages.

I need to convince the SAs that session replication is an un-necessary complication in this instance. I am looking for pros and cons of session replication so that I can better structure my argument.