The problem with intent is that you can't know what another person intends, and therefore you cannot make an accurate judgement about his/her intent. You don't get to decide what another person intends. You can guess, you can make an assumption, but you can't simply decide what another person intended by his/her actions. Assuming intent, be it malicious or benevolent, colours your opinion of the action, as demonstrated in this video. You say it's ok to ask for your number if one intends to actually get your number, but not if one is intending simply to be disruptive.