I have a quarry, which keeps its chunks loaded, outputting into buildcraft pipes. If I were to disconnect from the server, what would happen to the items in the pipes in the chunks that were unloaded? What about new items heading through pipes into unloaded chunks?
According to answer of Matthew Scharley here: https://gaming.stackexchange.com/a/81900
things won't move through unloaded pipes either so you won't get your materials till you go near the pipeline.
and comment of Jonathan Drain here: How many chunks do I need to keep loaded to keep quarries working in Buildcraft?
Everything fell out of the pipe at the point where it reached the unloaded segment.
I tried to test it and I think that the items in the pipes in the chunks that were unloaded will just stop. They will not disappear. For new items heading through pipes into unloaded chunks, I think it is very likely that everything fell out of the pipe at the point where it reached the unloaded segment, although I do not have enough time to test it and strong evidence to prove it.