What raw footage really looks like
It is not a longer version of your film. It is every clip a camera recorded, including false starts, camera adjustments, footage recorded at flat colour profiles that look washed out, and audio from separate recorders that has not been synced to the picture.
Working with it requires editing software and the patience to sort thousands of files. That is the honest reason most studios discourage it, not secrecy.
What people actually want when they ask
Nearly always one of three things: the entire ceremony, the entire toasts, or a guarantee that a specific moment was not cut. All three are better solved with a delivered edit than with a hard drive of clips.
- Want the whole ceremony? Ask for a full ceremony edit with clean audio.
- Want every speech? Ask for a complete toasts edit.
- Worried a moment was missed? Ask about it directly, it may already be in the footage and easily added.
If you still want it
Some studios will provide raw footage, sometimes for a fee covering media and transfer time. Ask before you book rather than after the wedding, and ask what format it arrives in and how long the studio keeps it.