Answer to Question 1
The legal systems of most countries include a concept called constructive notice. People receive constructive notice that they have become subject to new laws and cultural norms when they cross an international border, even if they are not specifically warned of the changed laws and norms by a sign or a border guards statement. Thus, ignorance of the law is not a sustainable defense, even in a new and unfamiliar jurisdiction.
This concept presents particular problems for online businesses because they may not know that customers from another country are accessing their Web sites. Thus, the concept of noticeeven constructive noticedoes not translate very well to online business.
Answer to Question 2
Power is a form of control over physical space and the people and objects that reside in that space, and is a defining characteristic of statehood. For laws to be effective, a government must be able to enforce them. Effective enforcement requires the power both to exercise physical control over residents, if necessary, and to impose sanctions on those who violate the law. The ability of a government to exert control over a person or corporation is called jurisdiction.
Laws in the physical world are grounded in the relationship between physical proximity and the effects, or impact, of a persons behavior. Personal or corporate actions have stronger effects on people and things that are nearby than on those that are far away. Government-provided trademark protection is a good example of this.