The point I was making was that even when foreign troops were extremely welcome in the larger context there were always likely to be resentments at a lower level and that when the troops were invaders speaking a foreign language hostility was to be expected. If the hostility was then suppressed by military action the inhabitants would not grow to love their visitors any better.
(Now I think of it, there is a flaw in that argument, I don't recall hearing that the British army in Spain and Portugal had a problem with their soldiers being murdered by the inhabitants, in spite of the implementation of the scorched earth policy.)

When you ask about how we know what the opinions of the people were, the answer is that we can't know. Saying the French people thought, or the British people thought, or the Prussian people thought, is always nonsense. Nations are composed of individuals and even within socio-economic groupings there are going to be different views, though it is probably fair to say that journalists are going to get excited about liberty of the press and the illiterate portion of the populace won't give a damn. Of course no-one asked the mass of the people about decisions on going to war (nothing changes there), - Napoleon certainly didn't.

Even when 'the people' did take an active role, as in Spain, it is difficult to judge what proportion were actively involved and how many were just trying to get on with life and keep out of trouble. Most popular uprisings are the act of a noisy minority. The least that can be said is that when the French became unable to keep military control of the conquered territories, they had no popular support to assist them.

regards,

Susan