I have never hosted a parrot. However, I grew up with parrots (my mom’s), and they can be messy AND destructive! I would definitely ask that they clean up around its cage and that the cage be placed where it can’t reach through the bars to anything surrounding it (furniture, curtains, blinds, etc.) And I would be very nervous about it spending any time loose in the house, which I’m guessing they would want to have it out of the cage some if they are attached to it enough to bring it on vacation.