I like the idea of getting in the first cruise you're at a new level. Then you can either keep it to reuse on future cruises or get rid of it if you don't care (and, if you lose them you can request them on future cruises). Not sure about having the tiered ones to purchase, would the cast members in the shops be able to verify your CC level (to ensure people are only buying lanyard for the level they're at)?
On our most recent cruise, my parents and I were all silver. I brought two silver lanyards I had gotten on previous cruises, but we needed one more. I knew we'd get them in our stateroom so I wasn't worried. We didn't get any, even though all three of us were sliver. We were able to easily go to guest services and they gave them to us, though, so no big deal.