Technically speaking, it looks like every mailpiece sent out of the US no matter how light or low value THAT HAS A CHIP IN IT must have a customs form attached!

Here are some rules:
Here's an article about the penalty for breaking the law and submitting a false form:
http://www.auctionbytes.com/cab/abu/y206/m01/abu0159/s05
I wouldn't break the law in any gross way. My concern is about bothering to include a form for "bulky" mail of low value chips. For low value chips, it doesn't matter, but for "bulky/thick non-documents you are SUPPOSED to have a form attached.

Here are some post office rules/overview:
https://www.usps.com/ship/customs-forms.htm
Seems they want custom forms on anything that is not a paper document:
"Generally, you’ll need a customs form for all international mail except First-Class Mail International™ items and Priority Mail International Flat Rate Envelopes that weigh less than 16 oz, are no more than 3/4" thick, and which contain only documents. ... ... What forms you need depend on the service you’re using and the declared value of your mail."
The above tells me that that if you use first class international mail that weighs a few ounces and is 1/2" thick, you still must use a customs form if it includes non-documents, that is, if it includes a chip!

Some more links:
https://www.usps.com/search.htm?q=customs%20form%20when%20need