Can a bidon cage be repurposed to carry a small first-aid kit on a bike, or are there better, more secure options for carrying essential medical supplies? What are the pros and cons of using a bidon cage for this purpose, and are there any design considerations or modifications that would need to be made to ensure a safe and accessible storage solution? Would a bidon cage-based system be suitable for both road and mountain bikes, or are there specific requirements for each type of cycling? Are there any existing products or DIY solutions that have successfully integrated a first-aid kit into a bidon cage or similar design, and what can be learned from these examples?