All audio waveforms are composed of sine waves. If a 1 watt sine wave @ 17kHz would blow the tweeter then either the speaker is very efficient or it cannot play very loud.

This is why I would like to see decibels rather than watts - watts are not what we hear. If a 17 kHz tone @ 90 decibels would blow the tweeter (similar to a typical driver in above scenario) then the speaker is very fragile and unlikely to be able to reproduce music well.

Make sense?