Gee, you guys are nasty!!
But sadly: YES.
Specs these days are written by promotion experts, who must look in the dictionary how to spell "watts". Since most has been said, I will not repeat.
Having been asked the same question over and over by non-technical people (a good sign: at least they are aware of an impending problem), I worked out that some guide might be given by looking at the system's power consumption. Hopefully the "manual" will give it on the last page, or it will be stamped on the back of the unit. A very wild estimate will be that, altogether, the total audio output of all chanells will sum to about 60% of that rating, maximum. Wild as said, but at least some ball park indication.