i think we are not entirely on the same page here. i did not meant the xterm, mrxvt, whatever terminal windows title (or rather, only indirectly), but the titles down in tmux's status line:
0: ksh 1:z!KB$+,*kB4EB4q*uEE"QCaKKEB-ot7B(Fu`E%B D0XD* 2:ksh 3:ksh running this: > echo \\033]2\;$(hostname)\\007 does not "clear" the tmux status line, only the terminal emulator's title attribute. also, when set-title is on, it clears certain part of the title but not all. it's very easy to reproduce this, just cat a binary file in your terminal (yes, that's my hobby ;-) -f -- if you pull the wings off a fly, does it become a walk?