Common wisdom in the US on spotting "suspicious" mailings - extra postage - why?

Mods: feel free to move to IMHO if you feel this question would be better there.

One of the common pearls of wisdom about determining if a package that you have received in the mail might contain a bomb or something similarly unwanted is whether or not it has extra postage. Why is this? Why would criminals put more postage than necessary on their bomb? Are they afraid that the post office will reject the package for insufficient postage and send it back, and the criminal will receive it back and potentially be injured or have their mailbox blow up?

It won’t be sent back, unless they’re stupid enough to put their own return address on the back.

More likely they just want to eliminate the possibility that it’ll be delayed or rejected.

Well, only a really dumb bomber would put their return address on the box!

Usually when I mail a package, I take it to the PO counter and have them weigh it and pay the postage. If I wanted to minimize the chance of being associated with that package, I wouldn’t do that. Now I have access to the internet and decent scales, so I could figure the correct postage, but in years past this was not as likely, so our bomber puts on extra postage just to be sure.

Yes, or even if they don’t have their return address on the package, it might not arrive at its intended destination.

I wonder what people thing of the all the one cent stamps I use every time the post office raises rates… For about a month after each increase, I use nothing but one cent stamps–I’m a jerk like that.

My understanding was not that the package bore more postage than was necessary to send that package, but that it bore more postage than would be expected for its size; that is, it’s unusually heavy. In any event, I don’t know how extra postage, beyond what the postal service would require for delivery, would be more discernible to the recipient than to the sender.

Yes, that’s how I understood it, too. Someone sending a “suspicious package” isn’t going to want to take it to the post office to be weighed.

I send lots of packages (not suspicious ones!) through selling stuff on Amazon/eBay. The rate of packages getting lost in the post is so low, in my experience, that it’s not worth my while to stand in a queue at the PO and get a proof of posting, so I just weigh the parcels at home, apply the correct postage, and post them in a pillarbox.

To cut down on my postage costs, I buy lots of old mint stamps at below face value from stamp dealers (typically 80%-85% of face value, sometimes less). Some of these date back to the 1970s, when postage rates were very low by today’s standards, so I end up using maybe six or eight big colourful stamps to post one CD. Whether this attracts any suspicion, I don’t know, but all the feedback I get suggests the items are delivered promptly…

Unfamiliarity with the US Postal Service might lead some visitors (welcome or not) to believe that different amounts of postage are needed for different distances that the package is shipped. I believe that most European nations do it that way.

None that I’m aware of. In fact, every country I’ve ever been to, whether in Europe or outside, had a postage system where a particular item would cost the same irrespective of where in the country you send it. Some countries used to have a special rate for mail that stays within the same city, but this has been abolished since (1) the rise of electronic communication makes inner-city mail much less important than it used to be and (2) most postal services have established a network of relatively high-level automatic sorting facilities where mail from a wider region is shipped to for sorting. Even mail addressed to an address in the same city may thus very well leave that city along the way.

Personally, I don’t find it very convincing to argue that a mail bomber who’s smart enough to build a parcel bomb is too dumb to run a two-minute search on the internet figuring out what sending a parcel of a given weight to a given address will cost.

In the USA, you can not put heavy packages in a mailbox (I think over 1 lb.) They must be brought to a counter for weighing. So even if you knew the correct postage, you still have to see a clerk.

Not true. I ship at a minimum 10 packages a week. I print my own postage, affix the label to each box and when taken to the post office, I deposit them on the counter and leave. Many times I have seen a clerk take my packages and deposit them directly in carts so they can to taken to the back to be scanned and readied to be loaded on trucks. I have never had a package returned for insufficient postage. I have also place smaller packages in my mailbox for my carrier to pick up, some have weighed up to 20 pounds. I put a post it note on the heavier boxes to let my mailman know they are heavy. If I am shipping priority mail, the mailman will come to my door and pick up the package, I just leave a note in my mailbox.

I suspect your Post Office branch knows you, and since you pre-print postage, you are an easily traceable source. You are not a typical, anonymous mailer.

Ever since 9/11, the USPO has been paranoid about mailing anything much larger than a #10 envelope. If I drop a 13 oz, prepaid, Priority Mail envelope in a public box around here, I assure you it will be returned to the return address immediately, with instructions to hand-deliver it to the PO window and pay the postage again.

The official PO regs say

It’s not for weighing reasons, but security, although they will weigh it anyway, just to be sure. Meanwhile, smile, as you may be on candid camera.

It’s the blue boxes on the street that don’t allow packages over 13 ounces. Basically, they want to eliminate the possibility that the next Unabomber can drop his packages in a mailbox on an abandoned street in the dead of night, without anyone seeing him (or her, I suppose.) In all of the situation you mentioned, there’s someone who could, in principle, identify you as the sender of your packages: either your letter carrier or the post office clerk.

ETA: Also, my memory may be faulty, but I believe that the 13-oz restriction pre-dates 9/11, and in fact was a response to the actions of Mr. Kaczynski and his copycats in the late '80s and early '90s.

Not to mention the postage, which he printed online and is traceable to the exact account holder.

Nah. Stolen credit card info via a unsecured wifi connection takes care of that.

Sure, but the USPO doesn’t seem to know that. They are treating a stamped package, which would be harder to trace, more carefully than an online printed one.

Anything can be faked – stamps could be counterfeited. It’s a matter of relative risk, and the USPO has to live up to their determination. What if someone comes up with a 12 oz bomb to avoid the 13 oz limit?