Many people are anti tube stows for a variety of reasons. We watch a lot of people using tube stows in the field successfully without any problems. We have also seen people having opening problems, then solving them through the use of rubber bands. If you are using tube stows successfully then keep going. But if you already have or develop inconsistent openings try tight rubber bands for a while.
Line dump occurs when the line stows are both short and loose enough to allow the lines to drop from the bag during the snatch of the bag lifting off your back. This may cause bad openings or increase the chances of malfunctions, due to out of sequence line deployment.
In the worst case, the locking stows may dump or more commonly break and dump the canopy from the bag before line stretch.
To reduce the chances of this happening, keep an eye on your stows and replace any that are worn as well as keeping your stows tight and line bites a good size.