No, not necessary or expected. But good-natured, tender hearted? Yes. If you can spare it, why not?
Answer from Michael Forrest Jones
, Beechmont Hotels Corporation
Every hotel sets its own rules on late check-out fees. Some (including mine) will give you so much extra time for the asking, some will let you stay into mid-afternoon for an extra twenty to fifty bucks, others will bill you for another night if you overstay check-out by five minutes.
As to leniency toward guests who've stayed several days, maybe a week or two, yes, we're more inclined to go along if someone has spent a lot of money, has otherwise been a good guest, and can be counted upon for lots of revenue in the future. But no matter how lenient we want to be with anyone, mid-afternoon (3:00 p.m. if that's the hotel's check-in time) is the drop-dead, 'turn into a pumpkin', witching hour.
Confessions of a hotel insider Jacob Tomsky.
Tip up front: Let the agent know you are serious immediately. Here's how I do it: I walk up, smile without showing teeth, give the agent my CC, drop a 20 on the desk, and say, "This is for you. Whatever you can do for me, I'd appreciate it." Boom. If I am after something specific, I will include that as well: "This is for you. Whatever you can do for me, I'd appreciate a room upgrade, late checkout, wine, whatever."
Ultimate Late Check-Out Guide for Hotel Stays  - UponArriving
You can also consider tossing them a 10 spot or 20 spot but the fee for late check-out could be around $20 at some hotels, so you may be better off just paying that fee instead of going the pseudo-bribery route.
How to Get Late Check-Out at a Hotel
A discreet $20 bill passed to the front desk clerk could turn a no into a yes
How-To: Score a Late Check-Out Time | Oyster.com
Sure, paying for a late checkout isn’t as ideal as getting the extra time for free but many hotels offer a half-day rate. The Mirage in Las Vegas allows guests to stay until three p.m. for a $30 charge, and many find it’s worth it: The hotel rooms are far more comfortable than the airport gate.