ISO file integrity check with md5sum

How often do you check *.iso files with md5sum.
All Linux binary images submitted with md5sum next to download link.
I never done that before, because I had believed that corruption is very rare!
One time I caught my eye on md5sum and made the check, and it unexpectedly FAIL!
I download *.iso again, now it PASS. 

So I guess it is not so rare!
Remainder for my self! Check *.iso files before using it!

To create checksum file:
$ md5sum ./linuxmint-14.1-mate-dvd-32bit.iso > ./md5sum.txt


File content:
$ cat ./md5sum.txt
9793c1e9c443241d156aace0446894dd *./linuxmint-14.1-mate-dvd-32bit.iso

You can create text file and copy file name and MD5 from the web page to check *.iso integrity.

To check integrity
$ md5sum -c ./md5sum.txt
./linuxmint-14.1-mate-dvd-32bit.iso: OK

I made Bootable USB stick from corrupted *.iso ,before the check and it works!
I wonder what consequences may be... corruption may hit only some application..? Can I expect crashes? How contraption can effect live Linux disk? 
Is this really the right way to distribute a binary image?

I'm not complaining! I'm just asking..? :)

md5sum check is fast and easy, bud maybe it's not for a user to thing about...
In a perfect World I would want notification about corrupted file after download is completed...  


I did couple tests with flash drive created from corrupted *.iso.
It depends on the part where the damage is done. It may boot up on one machine and make no problems;
O other machine it can freeze during boot with no explanation;
Also it may boot up, and throw "Installer crashed" during instalation;
So don't waste Your time, check *.iso integrity!