I think there is a confusion going on here.
On one hand, it does not report the discovered info to an interface.
It reports it to RouterOS, and you need to use Winbox/Webfig/API to read that information.
So, unless your users have access to your router, they can not see the list.
On the other hand, discovery packets on a LAN have a broadcast destination (sent to 255.255.255.255) by design, so every host on that interface can see all discovery packages, and there is nothing you can do other than turning off the sending of the discovery packets on ALL devices connected to that network (this also should include LLDP and CDP).
But they can not see discovery packets from other interfaces.
Torturing CCR1009-7G-1C-1S+, RB450G, RB750GL, RB951G-2HnD, RB960PGS, RB260GSP, OmniTIK 5HnD and NetMetal 922UAGS-5HPacD + R11e-5HnD in my home network.