NFL in 2010 (must PAY to walk through parking lot)

[bsmooth]

Its called trespassing.  If a place charges admission and you refuse to pay and enter anyway you will get arrested. Same thing would happen if you tried to enter Landshark stadium without a ticket to a Dolphin's game. 

There is a huge grey area to argue in court about tresspassing as you have described it and passing through a an open area.
Also do they have personnel on hand to enforce this rule 24/7 or just on game days?
Makes it kind of hard to claim your property rights are being trampled on when you only enforce it sparsely.

[MyGodWearsAHoodie]

There is a huge grey area to argue in court about tresspassing as you have described it and passing through a an open area.

Nope. The law is actually very clear.  Private property +  No permission to enter = trespass.   

Also do they have personnel on hand to enforce this rule 24/7 or just on game days?
Makes it kind of hard to claim your property rights are being trampled on when you only enforce it sparsely.

Are you suggesting some sort of easement by adverse possession? 

[StL FinFan]

Do you have to have "no trespassing" signs up to enforce the law?

[MyGodWearsAHoodie]

Do you have to have "no trespassing" signs up to enforce the law?

From a legal standpoint no.  From a practical perspective there needs to be some notification to a person that they can't be there before a cop is going to take action.  If a person was on private property w/o permission, with no  sign the landowner could in theory never tell the trespasser to get out, call the cops and the cops could arrest the individual.  I doubt that would happen very often in practice.  And in some cases such as an open lot, the person might be able to argue implied permission. Here the landowner told the person they either pay or get out.  Then the cop said pay or get out.  And then once they ignored the cop they got a ticket. 

Having a sign eliminates the implied permission defense.  But so does telling the person to leave.  Once they know they are not welcome and remain it is clear cut trespass. 

[Frimp]

If its a private lot, they can do whatever they want. But, if someone pays to park in the cash lot at Sun Life then wants to walk to an orange lot tailgate, charging them an extra $5 is BS.