If this is using a pair of low-end Cisco routers (as previous implementations did), it really doesn't take too many people doing this at once to "overload" them

If this is using a pair of low-end Cisco routers (as previous implementations did), it really doesn't take too many people doing this at once to "overload" them. Generating the responses is handled by the CPU (not the ASICs) and the processor in these devices is extremely underpowered, relative to, well, pretty much anything else with a processor in it. The processor in a Cisco 1841, for example, is an m68k at 250 MHz, if memory serves. Besides, I'm sure this was probably just something thrown together quickly for a good laugh and the responsible party likely didn't feel it was necessary to make this a highly available, fault-tolerant, geographically replicated service.