If you do not like that the medals shown over the head of the players will hide the "draw friend" icon (the symbol over your team-mates during team-based matches) for a while, you may want to not show them: it is possible to disable "draw rewards" with \cg_drawrewards 0 (default value is 1). They will be stored at the end of the match anyway (where applicable).
The server admin may replace the in-game behavior of the Excellent medal with custom Multikills messages; however, the "Excellent" medals will be stored after the match anyway.
About the Frags medal: The number indicates the frags, not the medals: "200" means that you have two of these medals: your frags are between 200 and 299, not 20000. When you reach 1000 frags, the number shown in the "single player" menu will become "1k", and will remain like it until you reach "2k" (it's rounded down to the nearest thousand); at the end of a match, instead, every 100 frags, you will still see the "complete" number, rounded down to the nearest hunded (1000, 1100, 1200, etc). After you get 1000000 of frags, the "single player" menu will say "1m" (rounded down to the nearest million), while the "podium" screen at the end of the match will still show the "complete" number, rounded down to the nearest hundred (shown when you get a new medal).