Cliffs:go here. read. be lernt. thanks me later
http://www.hometheatershack.com/forums/remotes-cables-accessories/5808-comprehensive-guide-splicing-speaker-wire.html
Standard practice? Extreme vibration? They're only used in very small motors and I always tape them. They certainly can come loose and I don't know of too many motors that run over potholes or are rattled by a subwoofer for hours on end. Totally different scenario. I've seen the plastic "shell" fall off of wirenuts leaving only the spring holding the wires together where there was NO vibration. Tape them.it's standard practice to wire up electric motors using wire nuts and that is an extreme vibration scenario. there is a correct way to use them as well. always tighten until there's two visual twists in the wire itself outside of the nut.
and there is no "extreme added resistance" by using them.