Oh no, not just on setuid root binary, no: several more too, plus a setgid procview one for good measure:

    $ ls -l /Library/DropboxHelperTools/Dropbox_u501
    total 328
    drwxr-xr-x  4 root  wheel        136  4 Apr 17:59 DropboxBundle.bundle/
    -r-s--x--x  1 root  wheel     139220 31 Aug 18:22 FinderLoadBundle*
    -rwxr-sr-x  1 root  procview   64368 23 May  2011 atos*
    -r-s--x--x  1 root  wheel       9632 31 Aug 18:22 dbaccessperm*
    -r-s--x--x  1 root  wheel     116668 31 Aug 18:22 dbfseventsd*
    drwxr-xr-x  4 root  wheel        136 31 Aug 18:22 mach_inject_bundle_stub.bundle/