Edit to add: If there really is a way to get the buyer's phone number, I'd love to know. Some shipping methods need a phone number, and thus far I've always just put my own in when this happens since I didn't have the buyer's one, and hoped it didn't matter.
However, I believe that amazon has discontinued the practice of giving out phone numbers as of early 2014 to sellers due to some idiot sellers harassing their customers.
But if you have someone's name and address, there is a decent change you can find it by googling their name. Especially if they have a land line.
edit: Yes, I also logged in just now and it does in fact show phone numbers. Not sure why I stopped picking them up through the api. They may have changed the field name. Also, it is strange that there are multiple complaints about not being able to see buyer phone numbers any longer in the seller forums. I think maybe they went away for a time and are back.
Edit:
> Also, it is strange that there are multiple complaints about not being able to see buyer phone numbers any longer in the seller forums. I think maybe they went away for a time and are back
Amazon experiments with Seller Central a lot - it's possible some people were getting phone numbers and some weren't for a long while. We also signup for many of their "beta" programs, so perhaps that makes a difference...?
We have a Pro account as well, and we see the phone number both in Seller Central as well as over the API (we currently are using a MWS API version from 2011, if that makes any difference).
Regarding putting your own number on the package - that is what we do with 100% of our shipments from our warehouse, and we've done it that way for more than a decade without issue.
The phone numbers are supposed to be mainly used for when there's an issue with delivery, but in our experience the carrier never calls (although it would be nice if they did sometimes... but I digress). We even put our phone number on international shipments (where I'd expect the most hassle due to customs), and never had an issue.
Of course, YMMV...
Probably for shipments shipped from an Amazon warehouse (sold by Amazon, or Fulfilled-by-Amazon/FBA).
For our own labels, we print our company phone number, and that's fairly common for many ecommerce companies (although certainly not all).
It protects the customer's privacy, and in the event there's an issue with delivery, it's best the carrier contact the shipper (us) anyway.
Some folks generate their own custom labels, and may omit things like that. The data is still sent to the carrier during the "End of Day" task (or equivalent) in whatever shipping software the shipper uses.
http://static-s3.sokoloff.com/random/amazon/IMG_1880.jpg
On other labels it's after the "DF3..." ID.
Apparently they chose to leave that field off the label, but it's still sent to USPS by the software.
If you give your cell phone number out to random companies on the Internet, then yes, you can expect to get spammed. What in the world makes that seem like a good idea to so many people?
As long as the junk mailer companies pay their postage, USPS is more than happy to deliver the junk to you.
I don't have any data, but I'd wager junk mailers are a sizable portion of annual USPS revenue...
Sellers are supposed to use them to fix order-related problems, and can be helpful for the case when a customer does not respond to emails (such as when you've provided an invalid delivery address).