Hey Anon. Forget about the brusing business, that's just an "old wives tale".
Personally i'd never shake anything that just had booze in it, the reason is
that shaking these drinks will dilute them to much, the ice should offer a
little dilution, but basically it's just there to cool the drink. Also,
shaking then will make the drink taste a little "slushy" if you know what i
mean.
Good luck & happy mixing.
Nidal.