I've read numerous posts and articles on dry hopping in primary, secondary, and kegs. My current brew calls (AIPA) calls for dry hopping. I've think, after reading these articles, that I'd like to dry hop in my secondary which is a glass carboy. I've also think that I'm just going to pour the pellets in without any type of hop bag, mainly for ease. I don't have a problem wrestling with getting the hops out after kegging: I'll just blast 'em. But does any hop residue (note not oils or resin, but actual chunks) end up in my beer if I don't use a bag? My main concern is that dry hopping without a bag may give me some "hop floaties" in my glass.
I'm not a fan of using bags in fermentation
The bags usually float giving a perfect media for bacteria on the exposed area to grow on. Expecially in secondary when c02 levels are the lowest. Also in a carboy it's very difficult to remove.
As far as floating particles
You won't have any issues by adding loose pellets, if you could crash the secondary and swirl occasionally just to break surface tension. It will all drop to the bottom. Just be careful to siphon well above the hop/trub bed.
Edit: I should add that there are ways to make sure your bag doesn't float. By adding sanitized stainless steel washers or glass marbles to the bag.