Apple is limiting iPhone Duo orders to a maximum of two per customer in the US, UK, and elsewhere after shipping dates slipped into January of next year within minutes of pre-orders opening .

The move appears to be an attempt to tackle the problem of scalping, where people buy large volumes of supply-constrained devices in order to resell them on eBay for well above the retail price …

Engadget reports that it tried to add more than two iPhone Duo units to its cart on the Apple stores in the US, UK, Japan, and Spain, and received a notification advising it of the limit.

We’ve tried adding more than two units to our cart on the Apple Stores for Japan, Spain and the United Kingdom, in addition to the US, and we’ve received a warning notice across all the online stores. The notification said: “A maximum of 2 iPhone Duo can be purchased per customer.…