A few newbie questions

I’ve searched this and other sites for answers to what I am sure are pretty basic questions, but I’m still stumped. If there’s a better place to get these answered, please point me there.

1. If I use the “Open VIDEO_TS Folder...” option of the Mac DVD Player to watch a video, should I generally expect the playback quality to be low (e.g., noticeable skips and jumps in both audio and video) compared to the quality I get from just playing it via one of the normal play buttons like it was a real DVD player? What if the VIDEO_TS folder in question is sitting on my hard drive rather than on a commercial DVD?

2. If I put a DVD into my drive and then drag and drop its VIDEO_TS folder onto my desktop and it copies with no problems, does that mean the DVD has no copy protection?

3. If I have AUDIO_TS and VIDEO_TS folders that I’m ready to burn to a DVD-R, what exactly does Roxio’s Toast (or other DVD burning software) do that a simple drag and drop doesn’t do?

Thanks for any help