There are different types of 'exploits'. Just because you wish to call it an 'exploit' doesn't mean it's not cheating. For example, exploiting knowledge you shouldn't have to buy/sell stock results in years in prison.
There is always an implied understanding
in online games that there will be bugs and if you find them you should
not exploit them for personal gain. World of Warcraft banned high end
guilds for exploiting bosses, Guild Wars 2 banned players for exploiting
bad pricing to make high end equipment, and Raiderz wiped a mammoth
amount of items off all their servers as a result of a duping exploit.
The cold hard fact is:
No, you're not so stupid as to 'think it was okay'
'Everybody is doing it' is not an excuse
You don't get to fall back on 'well they should have programmed better'
And you really are a twat if you try to say 'I used it 40x on accident'
If you used it you know what you did, and you know what you did was wrong and actively chose to do it because your personal gain was more important than any semblance of sportsmanship or personal integrity. You truly are the twat of twats.
How I would deal with the problem if I were Mobage:
24 hour maintenance and extension of the event. I would use this time to figure out everybody who used the exploit.
When the event came back, every damn person who exploited the glitch...oh lets say five times to be fair...would happily find themselves with 0 raid points.
This would move up the ranks of every honest person and send a message to people who think it's okay to exploit, and nobody would be banned.
After all, when my teacher caught me 'exploiting' another persons test (they should have covered it if they didn't want me looking) I would have received a zero.