yeah the whole being nice and respectful, acting innocent and non-threatening, and being cooperative is directly related to the "intent" judgement they'll surely be casting upon you. Usually you're looking at being arrested, or getting a summons, and potentially losing your stuff if it looks like you were "intent" upon trespassing. So if the area is fenced off, equipped with cameras and "NO TRESPASSING" signs everywhere, it certainly looks like you "intended" to trespass. So if caught, games up, you don't really have a case for your innocence... I'd absolutely be more honest, non-threatening, cooperative and respectful if I wanted to keep my stuff.
If you're in an area where say its not fenced off, its not clearly marked with signage, and there's low security then you're less likely to get a summons or arrested and you can still be nice, but you can also put on the dumb and innocent act like you had no "intent", you didn't even know you were trespassing, there were no signs, and you accidentally wandered over the imaginary line, etc.
just a look at how generally where you're at, how you present yourself, and your perceived "intent" from the police perspective could affect what happens to you and you're stuff.