Pioneer, for one, uses a global crossover applied to all channels. That means if you specify 80 Hz, it is applied to all speakers, and the LFE signal is also rolled off (high-pass filtered) at 80 Hz. This is a non-issue sonically in most systems, but was an issue for me (much lower crossover) and my scheme bypasses that problem. I am not sure that is the same as what you describe GoldenEar has seen. I have never heard of anyone rolling off the LF side of the LFE signal, but my sample size is limited.
"After silence, that which best expresses the inexpressible, is music" - Aldous Huxley