Your initial knee jerk reaction is going to be to act upon the angry feelings you have toward the individual interrupting your session but how you start the conversation can be critical to the outcome. More often than not the outcome is predetermined before any dialog goes down, however its never a bad idea to start it off on the right foot rather than burning any potential bridge that you may be able to erect throughout the interaction.
2. Be Polite as Possible
Perhaps it was being raised in the South, but I personally feel that approaching your disgruntled figure of "authority" with some manners throws them off of their game. Rather than being the dickhead that they are fully expecting to encounter, make them into the bad guy by simply being nice and polite when addressing them with your point of view. Defy the stereotypes that mainstream society has of our community and by doing so you will take away much of the ammo they planned to use against you.
3. You Both are Right
The whole reason you have gotten into this mess is probably because technically a law or two was tip toed around in order for you to be skating where you are. Thats the nature of our beast and just a fact of the Push Life. Most PED's will simply look the other way or don't care to take an interest in what you are doing BUT the one that did and is heckling you obviously is a stickler to some degree. When politely presenting your case, remember this character trait possessed by your foe and realize that you more than likely will not change the way they see the issue. They say you are breaking the law, and you are basically saying they are a square and you both are correct. Sometimes its best to just apologize and dip out for the time being...
4. Plan your Moments
No one can stake out your favorite spot all hours of the clock unless they seriously have nothing better to do and even then, they have to eat at some point. Plan your strikes when traffic will be lightest and you can go full Ninja on the spot while old grumpy gills is none the wiser. Sunday mornings and mid day during the week often are prime times to get some stealth shredding done but it various spot to spot so do some sleuthing of your own to see when you could slip in with no one being the wiser.
5. The Oldest, Cleanest Cut Individual Speaks
Sorry to volunteer some of y'all without asking but I have found everything runs much smoother if one individual steps up and acts as spokesman and the best person to do this is the eldest and cleanest member of the litter. The older the better too. If you have a spokesman who seniors the "skate stopper" the whole dynamic of the confrontation is shifted in your favor. Often they are taken off guard and way less mouthy toward someone who has a few years on them. If this mature figure doesn't exist in your crew, it still is in the groups best interest to not send the dread head forward...