I've just tried changing the shortcut for "Insert Render Frame" from "D" to "G" and things worked as I would have expected; inserting a frame by pressing "G" worked as before, and pressing "G" in a text frame gave me a letter "G" without inserting a new frame.
So it looks like there are some hard-coded instructions - as a.l.e suggests - for some functions no matter which single-key shortcut is used. If this is true then there's nothing the user can do about it and there's probably no work-around either.
It would be nice if there was some way that the user could be told this up-front rather than having to ask a question about it here. It's great that someone has asked the question because we can look to see what's going on, but it would be better if no-one else needed to ask the same question if the answer was obvious.
Either a message or some kind of colour/formatting change that can alert them to something that might have unexpected consequences would be nice. There's quite a lot of space on that panel so what about simply adding a message like: "WARNING: Single-key shortcuts may have unexpected consequences. Please use a key plus either SHIFT, CTRL and/or ALT instead."? It doesn't have to be complicated to work.
utnik: Personally I tend not to use most shortcut keys (except CTRL+S, CTRL+Z, etc.); it's just something I've not got used to doing even after more than three decades of using GUIs. I should really try though. However, I agree that it would be nice for people who use them to be able to have a good set of keys that do most of the usual functions. If I was asked which I would like I might offer: "[" and "]" for align objects left and right, and "=" for align objects centred (all horizontal alignments, while using a SHIFT modifier key would change that to vertical alignment). I think that sort of thing would be nice.