There is no place among the rules that guides this forum, that is stated that someone who is found of doing this, is going against the rules. It is clearly stated that having multiple accounts is allowed.
This is only partly true. It is true that having alternate accounts is not explicitly prohibited by the forum rules, but it may constitute a violation of established community norms as well as local campaign rules set by campaign managers. Of course, there are legitimate reasons for having an alternate account, but there are numerous situations in which using an alternate account is immoral, to say the least. For example, you are not allowed to use an alternate account for: evading a ban, bumping your own thread excessively, creating fake conversations between multiple accounts, participating in contests or bounty campaigns if prohibited by campaign rules, etc.
My question now is, is it a violation of law for hunters to send token to one another? Even if the linking address has nothing to do with the forum like in their POA? Why are many being accused of alt accounts even without enrolling multiple accounts in one campaign?
It depends on a case-by-case basis. Token transactions can be used to strengthen suspicion, but they are not necessarily evidence in themselves. Besides, the accusation itself carries no particular consequences other than inviting discussion.
It's like a depriving of freedom preventing users from sending and receiving token outside the forum.
I do not see how that would be possible.