Nice, and thanks for doing this. I'm responding because I do this also, and I wonder how many other domainers do it?
I've had a few domainers do me big favors over the years; especially one Chinese domainer who sold me my most important website domain... for less than he paid for it, and when he had offers for thousands $ more than I offered him. But he liked and believed what I was going to do with it so he took the loss, I did what I said I'd do with the domain, and he and I are good email-friends 3 years later now.
For that and other reasons I 'pay forward' my domaining skills. Most people, even many celebs' management companies, don't have much domain smarts and so mistakes and mismanagement happens. While I'm scouring the expired or pending delete lists, if I see someone's name-domain, even if it's a business or a non-famous person, I shoot them a quick email (if I can find their email addy relatively easily) telling them their domain has expired or deleted. I have a template letter I keep handy just for that, I just copy/paste it in and change the domain's name. Usually it's someone using the dot-net as their site, or with an extra word or initial or something. For the more famous, sometimes I grab their domain, reg fee if it's already deleted and available, or I'll consider using a dropcatcher to snag it if I see it dropping soon.
I never ask for or accept cash for this - of course, I don't pay more than reg fee or the dropcatch fee; if I were buying at auction and paying larger prices, I expect I'd like to get the 'hard cost' back. I also don't ask to speak to the celebrity in person, or for their email, I just contact their management or admin. It's a favor, paying it forward just for the karma, not a way to slide in the back door to meet-n-greet a celebrity. That's why I do it for the famous and also for Joe Normal. Much more often I do this for Joe Normal, actually.
I also do this 'under the radar', as you do. I won't mention past domains... but the only one I currently still have in my possession is BernieTaupin .com, which deleted a couple weeks ago. Bernie was famous as the primary lyricist for Elton John's hit songs and became arguably the first 'famous lyricist'. Still no reply from Bernie's web admin or management. Sometimes the emails just don't get through, sometimes they get through but the management doesn't think it's important for whatever reason (or they think it's a scam and they ignore it), and sometimes the celeb actually just doesn't care and is happy with their current domain.
I just keep a 'this domain is not for sale' sign on a blank landing page for any domains I do get on someone else's behalf. If I can't make contact or if they're not interested, I don't try sell the domain, I just let it drop after a year.
Anyway, all that was just a long 'thank you' for doing your part, I understand why you do it. And also I'm wondering how many others do this?