I have done this with Summer and also with Sunshine. Both their bonded friends were able to accept quickly and easily that their friend had gone and why. Roger and Tilly even covered Summer's head when they had 'finished' with her. They were able to move on quickly. It just means that there is a level of understanding, as opposed to, like clutterydrawer said, vanishing, which can be very distressing for them.
I once saw a video of a bun who had died and his bond friend and it was so clear from that video that the bondmate needed that time to accept. She dragged food over to his mouth and tried to make him move, and when she realised he wouldn't she hopped away and carried on.
I have found this is very hard for me to do but beneficial for my buns. I wouldn't do it in all circumstances though, each one is different.