upgrading emacs when emacs is still running

Every time on Debian I use aptitude to
The following packages will be upgraded:
  emacs-snapshot  emacs-snapshot-bin-common (for emacs-snapshot)
  emacs-snapshot-common (for emacs-snapshot, emacs-snapshot-el)
  emacs-snapshot-el
I have to remember to exit any running emacs sessions first, lest
later encountering problems when old emacs reads new .elcs, etc.
Updating Firefox never has such problems.
OK, hard to work around, also too much fuss to put warnings into the
Debian update script: "a running emacs session was detected, proceed?"