I had the same issue with my Nocaster Relic.
I used clear nail polish and have not had a problem since. If I do ever need to remove the barrel tip, it won't be too hard to do.
Works with wire cutters too.On my strat I just pinched the metal switch tab with some pliers till there was a little burr for the switch to grab onto.
This or tape have done the trick, for mine.Short of dropping some glue inside the switch tip, try what I did: wrap a small piece of paper around the selector, then push the tip on. Should do it.