It's not so much that it 'crashes' 9-11, it simply ties up all the available operators so there won't be anyone available to answer the *real* emergency call coming in at the same time -- there's only so many dispatchers available to answer calls, after all. Too many calls is too many calls, regardless of how competent the initiator is.
Other than prioritizing certain calls (e.g. the ones that haven't been calling you a thousand times already today) there's not a whole lot you can do to mitigate this while remaining available to everyone.
(There often already are other call routing prioritizations in place, e.g. if there is an incoming landline and cellphone call at the same time and only one dispatcher available, they'd typically answer the landline first -- A single car accident on a busy freeway can generate dozens of incoming cellphone calls reporting the same accident, while a landline call is more likely to be a new incident that needs action.)