My one Achilles heel with Perforce is that occasionally I will have a named CL on the go, then notice something else that needs fixing, check a new file out, apply the fix, test my changes, and then submit the named CL, forgetting that that one other file is in the default CL rather than the named CL. Most of the time I'll have the presence of mind to move the file immediately or check before submitting. Occasionally I won't. The only times I ever break the build, it will be because of this.
Does P4V have a facility to warn you about still having unsubmitted files in another CL? I'm not the kind of person to have multiple named CLs on the go at the same time.