I do not know if freebitco has such feature that allow their users to send funds to another user fast and free using the ID
If there was a feature like this, perhaps many multi-account users would use this feature to collect all funds into one place and then withdraw them, because the withdrawal fees might be quite large for free users and those who are still looking for free bitcoins from this site by using the free roll feature because of the income only a little under 5 satoshi or even less depending on user activity, I myself only get 6 satoshi per free roll every hour, so it might take weeks to be able to make this withdrawal where the minimum withdrawal is 30k satoshi.
But I'm sure if there is a feature where every user can send each other of course it will be misused even though I know that security on this site is also very tight with multi-account user accounts, but whatever it is, people will definitely look for loopholes to be able to get free bitcoins quickly and then collect them. all funds from the clone account to one account which becomes the main account to withdraw all the free bitcoins obtained from this site, but actually this site only lacks features for interacting with the admin or service support because whatever it is, it is definitely important for users to be able to complain about all the problems.
Fairly good point about this "fund collecting", also I would think that most people would use it out of reason that you get daily interest at freebitco.in , which is quite amazing feature I have to admit.
Combine that with referral net of alt accounts transfering funds between them and most likely they would abuse it to get their daily satoshi interest higher and higher.
One thing in your post makes my wonder why would you say they have "very tight" when it comes to multi-account user? Have you seen some examples of alt accounts banned or something?