Is this what you mean? https://www.canex.ca/en/explosive-ordnance-disposal-499999308837
Earning a badge that is the equal of a CAF specialist/trade badge is mark of respect, to me at least. For a CAF member, wearing it on your body is similar to wearing it on your uniform. It would be like wearing a Super Bowl or Stanley Cup ring...even if you've never played, just because you found one you could buy on Ebay.
To "earn" the badge, in the military, you successfully complete the training and professional requirements needed to be 'qualified' for that badge. Example, I wear the Wings of my trade on my uniforms, and they are part of a 1/4 sleeve tattoo I have as well. However, I don't have the Parachutist Wings as part of my tattoo, because although I went on my Basic Para course, I was injured and removed from the course before completing the required 5 jumps to earn the Basic Parachutist qualification and wear "Jump Wings" on my uniforms. I never attained that qual, so I never 'earned' those Wings. I'd never dishonor those how have and those who will complete all the jump training by wearing the Parachutist badge/Jump Wings...and I'd also never want to dishonor myself and my family name, either.
It depends on the unit and their traditions. My unit gets a calf tattoo. When I joined the requirements for the JRs were a little more stringent and were definitely enforced. As time went on the rules became a little more lax for a number of reasons, but for sure at the very minimum you must be a fully trained and contributing member of the unit; generally those that get them are Corporal and up.
By completing whatever TQ3 is called now and obtaining the rank of a sapper vice private. It’s not an obligation, get it, don’t get, it’s more about what it means to you than anyone else. It’s on my list.