I don't mean to be difficult but...
1) A confirming signal of what? You've mentioned low-volume trend, so you already know markets can trend higher, lower, or be range-bound, regardless of increasing volume or decreasing volume. What signal is confirmed by low volume?
2) What would be cause (for institutions) to "feel fine"? Why would there be a "need" (for institutions) to trade against a low-volume trend? A trend can occur with decreasing volume, right? Maybe it's as simple as an unattractive bid and-or ask price. I think a "better" question might be, why aren't they using the reduced volatility to continue accumulation or distribution, whichever jibes with the trend they are participating with in the first place.
As mentioned, not trying to be difficult, I just don't quite understand what you trying to say, ask, or point out.