I am adding my belated two bits here on your question, Peter, and it is simply that I agree 100% with the thought given that if the consequence has served its purpose and it is no longer a problem, freely and happily drop it! Congratulate them (and yourself) for having moved forward. If I continue to give a consequence for their very occasional forgetfulness, what happens when I forget things too?
Along a similar vein — at one point last year I noted that the number of students “needing” to use the restroom during class time was becoming a problem. My normal policy is that if you went after recess, you may go again without a consequence. They raise four fingers to request permission and I mouth to them the question, “Did you go at recess time?” If no, they may go, but need to stay in five minutes of the next recess. If yes, and it seems to be an appropriate time, they may go — only one child at a time. When it noted that the number of students “needing” to go had increased quite a bit, I merely made a graph with each child’s name on it and if going an extra time, they simply made a tally mark behind their name. That was all. No other consequence. Immediately the numbers decreased. I had also added my name and made my tally marks as needed. At the end of the week(s) we noted how many tally marks total there were. After only 2-3 weeks we simply stopped doing it; the problem had disappeared.