What a request really is
A request is information: one dancer telling you where they want the night to go. Sometimes it is brilliant intelligence — the record you would never have risked that turns out to be exactly what that floor wanted. Sometimes it is one person asking two hundred others to have a different night. The DJ's job is telling those apart in three seconds, mid-mix, while doing everything else.
The professional answer is almost never a flat yes or no. It is: does this record serve this floor, in this arc, in the next twenty minutes? A good request gets woven in where it lands hardest. A wrong-room request gets a genuine 'I'll see where it fits' — and if it never fits, that was the honest answer.
Private events are different
At a wedding or private party the guests are not strangers — they are the whole point. Requests there are taken seriously, inside two guardrails agreed before the night: the must-play list, honoured; and the do-not-play list, respected without exception, even when a guest asks sweetly at midnight. That last clause matters — the couple or host outranks the request, always, and a professional holds that line so you don't have to.
Setting the policy for your event
Decide it at booking, not on the night. Open floor for requests, requests filtered through the DJ's judgement, or a locked brief — all three are legitimate; what breaks nights is nobody deciding. Tell the DJ which regime you want, hand over the two lists, and then let the reading of the room do its work. A floor that trusts its DJ requests less anyway: the records keep arriving before anyone thinks to ask.