Never thought about using an open faced reel mostly because I would do exactly as you have mentioned. I would forget to flip the bale.
3 things could happen you watch your 6 dollar fishing arrow fly off into the sunset, you watch expensive parts from the reel fly off into the sunset, lastly and most unpleasant the arrow doesn't break anything off and comes flying back at you. Other than those negative Nelly comments it should work fine.


When I was a Student I used a piece of PVC pipe that I taped to the front of the bow. The 90lb test woven thread was wrapped around the outside. I shot through the middle of the pipe and the thread spooled off the pipe lickety split. Worked great. Granted it required a little effort but it was cheap and cost almost nothing to replace. I have pictures if you want to see them I'll dig some up.

 

I would suggest getting a reel setup. It doesn't need to be that expensive. You can get a reel seat that screws into the stab hole for $20, a spin cast reel for around $25, 100' of fast flight line (two complete spools for your reel) for about $10 and some arrows that you can throw together for around $15/a piece. I am going of the prices from Backwater Bowfishing http://www.backwaterbowfishing.com/onlinestore/cart.php. If you hurry, I believe they are running a free shipping deal.

 

Hey guys thanks for the insight! Actually managed to nab a "broken reel" from my Teaching Outdoor Skills class. My course instructor thought it was broken because the reel wouldn't work after pushing the line release button. Told him I could probably fix it, to which he replied "good luck." Popped off the bell cover and found some line had gotten under the metal bell (least I think that's what it's called). Not five minutes later I had a perfectly working spincast reel Though I may just give it back to him being it was technically school property and I'd rather not cheat the school out of something like that. It's only a Rhino RSC3, a pretty cheap reel in my opinion.

 

metal coffee can, steel mount made from strapping material (if it has a lip on the end, cut that off as the string can get hung up on that). simply make a "U" bracket from a piece of strapping material, screw it in 4 places to the coffee can. The fishing line is wrapped around the can.

What Bow Bender mentions works very well too...

don't use too much weight on your bow fishing rig as it's real easy to get the arrow stuck in the river bottom/bank.