Well I guess that answers the question whether the commercial micro-SD cards are worth the money.
Have you considered buying an grade Micro SD? industrial grade Micro SD? Does anyone know if the new 10-10-2017 image can boot directly from a USB device? Currently my system boots to USB as per https://sourceforge.net/p/raspbx/discussion/general/thread/beb0605a/ but it would be nice to remove the SD from the boot cycle.
Although there is no direct way , you could intercept the call before it is placed, but after the person has dialled the number. Then play your prompt and proceed from there. So they call the number, RasPBX plays your prompt and then if everyone is happy places the call.
Thanks for making the script. I have tried it and it does all the steps correctly but will not boot from an Intel SSD connected via a X800 expansion board or from a USB stick. I have tried the latest version of Jessie and used the backup SD card option to backup to the SSD and the USB stick and it worked a treat on both devices so I know it can be done. The Jessie image uses the partuuid information instead of /dev/ which means you can just copy the disk without changning any parameters.