No it won't cause any issues, there is a technique to opening FF cultures to stop the vast majority of escapees. Follow these easy steps. (I will make a video for this tomorrow and post it up on my youtube channel (link in my signature).
1. Have a bowl or cup ready for FF (this means it has supplement powder in it already and is clean---- Wash with hot water and use no soap. Rinse with Dechlorinated water)
2. Tap the FF culture on the bottom several times (fairly hard the goal is to knock all the FF to the bottom
3. Open culture and start tapping it on the side of the feeding cup
4. Once enough flies are in the feeding cup tap the bottom of the FF culture to knock them back down and put the lid back on quick.
5. Gently shake the feeding cup to coat the ff wight he supplement. (this will also make them to heavy to climb
6. tap the feeding cup in the tank to deposit ff for frog.
The cup actually works best is it is pretty deep. This will help you maximize the time you have to get the FF culture sealed back up before the files climb out of the cup. Another thing you could add is to tap the feeding cup on the counter or table while tapping the ff culture on the cup. This will continuously knock the ff to the bottom of the feeding cup. After a few tries you will be a pro at it.
Culturing you own FF is the way to go. It is WAY cheaper than paying $9.99 or so per culture. The same site I sent you links to for wood and Springtails NeHerp has some pretty amazing FF media. Get a 5Lb bag of the FF media and 25 or more Deli cups with vented lids. Also get some excelsior (they sale it in various sizes. I would recommend getting the box of it. It will last forever and is the best bang for your buck.
I plan on making a "How to make FF culture" video as well and posting it... Might do that tomorrow too. I use the Neherp media so you can see how I do it with their media. My cultures produce a crazy amount with the NeHerp media.