As Dakeyras pointed out, Fate is all about the narrative. This doesn't just mean that there has to be a justification for invokes : said justification should probably be included in the description. It's not just "I invoke Cyber Legs for a +2 to my Attack" but "I'm kicking him square in the face *rolls, sees a success with style just out of reach*... using my Cyber Legs at full power for maximum effect".
On the Arms race side of things, it's more of a player mentality issue to me. Generally, a player should let his competitiveness aside when playing Fate. Of course Pwning is awesome, but Fate characters are not supposed to be awesome all the time. Where's the Drama in that ? That's why aspects can be compelled against them. That's why failing a roll can still be a success but at a high cost. That's why at some point, you stop piling the Fate points and take your Miss as an opportunity for Interesting Failure. So you were Focused on the target, Lurking in the shadows, using an Enhanced Scope and still missed your shot ? Time to wonder what went wrong. Was the quarry prepared for you, maybe ? Were you double crossed ? It's possible that in the next few exchanges, you're going to get a nasty shot to the shoulder, concede by hitting the dirt and swear revenge on whoever it was that made this fiasco possible.
So... while nothing in the RAW prevents anyone from doing this, this behavior should be reserved for instances where the players/GM want to absolutely, entirely focus on a few rolls, such as a final showdown with the Dragon, or the one time in the spotlight where you want to show off your aptitude in the most awesome of manners, fully knowing that you'll be draining a lot of your resources (which may be very scarce to begin with depending on how many stunts you started with).