I haven't brought a paper ticket in about 5 years because the damned things kept becoming demagnetized. Pretty cool about the youth discount.
Aaron Gibson at
BART board approves 50-cent surcharge for paper tickets, expanded discount for youth
In an effort to move people to Clipper cards, BART’s Board of Directors on Thursday approved a 50-cent surcharge on paper tickets, which will go into effect on Jan. 1, 2018.
Another aspect is that this is incentivizing users to identify themselves through their usage patterns.