Nothing major - can't really be abused into duping other items..as far as I know.

https://www.youtube.com/watch?v=2qTh9erQaLo

Also can the reviewer of this check my question on this ticket:
#2129

that's a weird bug, what MC and BC version is this?

This is 1.7.10 FTB Infinity Evolved, and my buildcraft is 7.1.16

@AlexIIL is this fixed for BC 8.0 with the rewrite or still a problem? i'm also guessing we won't see a fix on the 7.1.x branch?

almost definatly was caused by another mod messing with the builder, if someone can reproduce this and provide a modlist with 7.99.3 we can take a look