A person must actually consent to your marketing, before you invite him/her to like your page.
Among other things, the Consumer Ombudsman states that:
“A company is only allowed to invite you to like its page or in other ways contact you via your Facebook profile, if you have authorized the company to do so. The same rules apply as with the traditional e-mails. In the eyes of the Marketing Act, both forms of communication are considered to be e-mails.”
“The social media has given businesses new opportunities to contact consumers directly. But though it may be easy to contact consumers, it’s not always legal. The consumer must in advance have given clear consent, before companies are allowed to establish contact. However, the development of social media necessitates that we constantly review our interpretation of the legislation.”
Read more about the Consumer Ombudsman’s decision here.