[formerly_proven]

Oh, true! I thought it was the MAC address in tiny print on iPhones but it's actually the FCC ID and IMEI. On the other hand, all smartphones have the MAC and serial number easily accessible in their settings menu.

[jaywalk]

You must not have seen an iPhone in quite a while. There is absolutely nothing printed on iPhones these days, all of the regulatory stuff is under the Settings menu.

[cookingmyserver]

Depends on the country. Although they have been hiding it pretty well, and usually it is only symbols and not detailed information like IDs.

[b112]

Many phones let you rotate your MAC too, to prevent profiling...

[djrogers]

> I thought it was the MAC address in tiny print on iPhones but it's actually the FCC ID and IMEI.

iPhones haven't been doing that for years - they have no markings other than the apple logo on the back.