This is just a small hack inspired by a post I read the Raspberry Pi forum.

A few weeks ago I bought a combined Micro-SD Card and USB-Adapter on eBay (from China).

I opened it and cut off  the USB-Adapter part as I am only interested in the SD-Card part of the adapter.

The result may not be the visually most convincing hack but it works perfect and reduces the chance of accidently pulling out the SD-Card.