When booting the installer from a USB stick on a Lenovo X60, X61, or T61 Laptop, anaconda orders /dev/sdb (the usb stick) before /dev/sda (the disk in the laptop) and subsequently installs GRUB to /dev/sdb (the usb stick). The first boot subsequently fails. If the order is changed manually in the Advanced options, it works. This has a high potential do cause high call volume.
Is this a regression from RHEL4 or from an earlier release of RHEL5? I'm guessing on RHEL4, as installation to USB devices was first introduced with RHEL5 GA. This is actually a side effect of supporting installation to USB, as you may very well have a large USB disk that you really do want to install the bootloader to. We have no way of telling whether something's a large USB disk or a relatively small (and not likely to be frequently attached) USB key. So, we just have to go with the full support. If you deselect the USB device as a device to use on the initial partitioning screen, I believe it should get removed as a possibility for installing a bootloader to. If you really feel this is a significant problem for 5.3, we can add a release note explaining the situation. However, as far as I know it's been this way throughout the life of RHEL5 and there's not really anything to do about it.