A physics question that's bugged me in Many Universes is whether it requires energy to "create" the alternate universes, and if so, where it comes from. If your supposition of merging universes is true, that would provide symmmetry at least -- allowing for a visualization of "boiling universes", like the boiling of particle/anti-particle pairs at zero-energy; if merges matched splits, we'd get net zero energy integrated over time. Also no net change in the number of universes, which kind of kills the point of Many Worlds, but whatever.

Certainly merge conflicts from alternate universes would explain where my socks go when I'm not looking.