Feel free to express your ideas and opinions to the staff present. But my experience at these events is that the response you will get is essentially an in person version of the “we will pass on these thoughts to the relevant departments” email.
In most cases, what you have to say to the management is not the first time they have heard it. They are usually rolling their eyes internally or externally.
Totally agree but when I first met Nicholas at one of these (before he moved on) some time ago I left him with a handful of action points and he followed up with me personally on all of them so clearly I have had a more useful experience than others at these events.