I think this is why they provide the option of multiple retainers. SE feels you should BUY that privilege, not have it handed to you. Basically, if you need more space to store the stuff that you willingly decided you want, buy another retainer for 1$.

I know that many will disagree with this, but above all else, SE is in the business of making money, and convenience comes at a price. They put the "purchase extra retainers" system in place for a reason.