To be fair, it may not have been the dual boot itself that was risky.
Unless they had a dedicated harddrive, they would also need to resize existing fat32/ntfs partitions and add a couple of new partitions for Linux. This process had a certain risk.
>>throwa+(OP)
I have vague memories from early days of using Linux that you used to have to manually set the modeline for your videocard in X11 - if you got things wrong you could potentially permanently damage the monitor.