"Short Sector” means Less Loo Time per passenger,and the whole amount of time free of dangerous turbulence needs to be fully used. Extreme cases of holding your wee wee are bad for your health and in some cases even eventually fatal. So, particularly on a short sector seat belt sign should, no, MUST, be used only to avoid danger, not for convenience.
If you “nail them to the seats” you may find that you have unusable seats for the next sector”.