You're right, Gord. Strange and unique way to do things. Never saw that before, but that's the way my Carvin "All-In-Ones" (the same unit(s) Boo has) work.
Still, the rule of not hooking a load with less impedance than required by the Carvin stands.
Always been partial to Carvin equipment since I toured the factory in Covina in 1962 as an impressionable 15 year old.
One of my Carvin PA heads (200 watts-6 channel) sees 4 nights a week duty continuously since 1995.
The little 12' combo is older than that. Inexpensive, too.
Russ