Why would anyone in their right mind be tempted by this since tickets and upgrades are already transferable, or do they have plans to stop that?

http://transfermiles.ualmiles.com

New! Now you can share your miles with friends and family. For a limited time, transfer up to 60,000 Mileage Plus� Transfer Miles!
Give up to 15,000 miles to each recipient's account
Allow 7 business days for the miles to post to each recipient's account
Credit card will be billed immediately for transfer
Program fees and mileage rates subject to change
Minimum transfer 5,000 miles per account
Frequently Asked Questions
Check order status after purchase

Mileage Plus Transfer Miles cost $0.01 per mile (includes applicable taxes) plus a $30.00 transaction fee

I got the email too. I think it is highly unlikely that they will stop people from giving awards to others.

They just send this email out periodically to remind people that the opportunity exists and maybe to catch a few suckers.

And it could be a useful promotion for people who don't fly alot. Two people with 10k and change in their account -- they can effectively combine their balances and get something with what otherwise would be useless miles.

But as qasr said, it's mostly for suckers.

Here's why: I am 1K with approximately 750K RDM's. Mrs. bseller is GM with approximately 190K RDM, and doesn't generally travel on UA since her company forces her onto AA. When we travel together, I am likely to pay and UG with SWU's, while simultaneously using my RDM's for her tix. But next year I need to gift 2 FC tix to my parents for their anniversary, and I won't have the luxury of "waiting" for saver awards to open.
So, I may very well need to redeem one (or 2) 200K FC award tix ORD-Europe. If that's the case, putting the 10K RDM's in Mrs. bseller's account is a cheap way to: 1) Utilize miles that need to be spent anyway, and 2) Keep my account balances up since 1K's have better opportunities for changes/refunds, etc. of award tix....
Hope that helps! Best wishes, Dave