No, it is not obvious.
Read, please, what I describe in may topic "cunnilingus".
I descovered a little hole in the condom, but the condom did not broke, and when I pulled out, the penis was ENTIRELY covered.
And I'm still asking to myself: did my penis work out of the condom in that brief intercourse?
From my personal experience i can tell you that you would know if the condom breaks. Trust me!