A first year CS student would have caught it, however, when you're dealing with the embedded world, sometimes you have to do things like convert 64 bit floats to 16 bit ints to get things to fit in the 2k or so of ROM you have to work with, or to run in a reasonable amount of time. The problem lies more in the blind reuse of code, and a lack of documentation as to the code's constraints. Something like that code, I'd have commented to the effect that it only works up to x meters per second and/or put something in my own code that if the value exceeds some certain amount, to return MAXINT or a value like that. Again, yes it's ugly, but given a the environment, sometimes you have to hold your nose while writing out the code.
I think it is way more likely that they never read the documentation (or at least not all of it) than that there was no documentation.
Also, that 'clip to MAXINT' choice can be a very bad choice, too, so it would have to be documented and that documentation would have to be checked before any reuse of the code in environments with the constraint that the code cannot fail. Because of that, I cannot see how that choice would help to prevent such accidents.
