Can police trespass to issue a ticket?

I live in the western suburbs of Chicago where village stickers are required for every vehicle you own. I recently was pulled over for speeding and issued a ticket for not having a village sticker, and paid this fine.

Two weeks later, my truck was parked in my driveway (not on the street) and I found that the police had entered onto my property to issue me another "sticker violation" ticket, $50.

Is is legal for police to trespass to see if I have a village sticker and issue a ticket?

Sorry, I know this isn't a traffic issue, but didn't know exactly where to post it.

Thanks in advance!

Unfortunately, yes they can, to a point. You see, depending on what state you live in, either the first 6-12 feet of your driveway, yard etc. are "public property". Meaning it is legal for anyone to just walk on your yard, and you can not tell them to leave unless you have a posted "NO TRESPASSING". I know, this law is stupid, but, it is the law. But, if your truck was further into the driveway (you may want to look up how far public property actually is), you may be able to fight this ticket. You might also want to make a quick trip to Wal-Mart and buy a sign, and possibly a permit if you need one to have the sign legally posted, and this will rid you of police officers, or people in general of coming onto your property.

Sorry this isn't too responsive to your question, but -
Is the sticker required to simply possess a vehicle in the village - or to drive a vehicle on village streets?
If the latter, I could have the vehicle on my property without a village sticker (just as I could have one on my property without a state license plate), I simply couldn't drive it on a village street.

I guess my question would move more in the direction of -
If it was a privately owned vehicle on private property (maybe driven on village streets - maybe not), what business would they have giving you a ticket anyway?

wtd