Offline to Online with DSLR, GoPro and other non timecoded camera files

I recently had to deal with GoPro footage shot in slow motion - 720p/100.
The footage doesn't import well into Media Composer. The files play back at normal speed at 100 fps instead of playing slow at 25 fps. One second of footage should be 4 seconds to play back, and it wasn't. I got the same results in various project settings (25p, 25i, 50p...)
The workflow that best worked here was as follows:

• Import footage to Adobe Premiere Pro into a 25p project
• Select all clips, optn/ctrl click and choose Modify -> Interpret Footage and click Assume this frame rate - 25
• Drag all clips to a new 720p/25 sequence (optionally ctrl click and Unlink Audio)
• Click on the sequence you created and choose File - Export - Media and choose your favorite format. I chose DNxHD 185 720p/50 10 bit because it imports very quickly into Media Composer as it only doing a re-wrap and not actually transcoding the file, and it's good enough for television mastering.

What you end up with in this workflow is one long file, an equivalent to a digital tape, from which you work both your offline edit and finishing. It's the easiest and quickest way to conform your online (only one file to link) and saves an extra transcoding job.
This workflow will work fine for television. When going to bigger screens, DCP for example, it might compromise quality too much.
This workflow will suit most non timecoded camera files such as those from DSLR cameras, GoPro, mobile phones and others.