why "spectator", why not "viewer"?
A viewer is someone watching TV - telespettatore
I suggest you to translate "ticket" as "biglietto" (something you pay) and "note" as "appunto" (a reminder). In this last case the word "biglietto" is correct too, but DL asked you to translate something that you pay, so "note" couldn't be correct.
I put 'every spectator purchases a ticket' - why is this incorrect?
Why not "every" spectator, one of the definitions Duo gives for ogni?
I have" every spectator" but apparently this is too much for Duolingo course contributor to digest.
If viewer is incorrect DL should not have it under Sports cards as the translation for lo spettatore.