Need i code sth in the server to clear the bounded objects when some client crashed ?
I am not sure what "sth" means, but no, you don't need to handle client crashes. Some people chose to implement Undereferenced interface, but it's not going to give you any points, and they may actually penalize you.
Indeed. It can't be said often enough: adding complexity may well work against you. Stick to the instructions. It should also be said however that adding Unreferenced cleanup may add only a few lines of code (literally three lines for me), and it would take a very pedantic assessor to penalize you for adding a trivial amount of code if it brought significant benefits. And indeed, in my case at least, he certainly didn't penalize me for it.
Originally posted by Eugene Kononov:
[...] Some people chose to implement Undereferenced interface, but it's not going to give you any points, and they may actually penalize you.
YMMV. Yet another design decision to make...