To enter an amusement park without paying the admission fee knowingly (and/or stealthily) is a form of theft. To take another’s goods unjustly and against the owner’s will, when he has every reason and right to be unwilling to be deprived of them, is stealing. Such an injustice causes the owner to lose monies that are rightfully his. To take and use another’s property unjustly is contrary to the seventh commandment: You shall not steal (cf. Ex. 20:15; Deut. 5:19; Matt. 19:18; CCC 2454). The fact that the amusement park owners didn’t block access to the path doesn’t give anyone license to enter without paying.