It will go down pretty far - maybe an inch...
to get an idea here is a link ot a card I just made and used the punch
Gallery at Splitcoaststampers
I could have gone down a little further and punched - I went thru my square cut out to put the rectangle punches.
You can always do 2 little slits to feed the ribbon thru to if you need it somewhere the punch doesn't reach.
The thing about the punches is that when you buy from SU you are not sure which brand you are going to get. They order from different suppliers.
I bought my large square punch from Micheals and a friend ordered hers via SU and it is the same one...the price difference between what you can buy them for at Micheals or some craft store at retail vs SU is about $1-2. I bought mine with a 40% off coupon - just means more $$$ to buy stamps with.
Some of SU stuff - Fiskers cutter, punches, staz-on, versamark, paper crimper are all made by other companies - even the Cropper Hopper - mine is identical to the one my friend bought from SU only hers is black and mine is blue and you can easily buy them at Micheals, Wal-mart and such for cheaper.
One thing that I have found is that it is CHEAPER to buy ribbon thru SU - for the amount you are getting 25yards...it works out to about .20-.25 cents a yard - much better than .50+ cents a yard at craft stores...