It seems to me they probably wouldn't have gone full-on about it if the oshi-jumpers had listened to the first notice (against just excessive jumping)?
I'd never thought about it before, since I've never been able to attend a concert thus never had to deal with people around me, but once the rule came out I kept reading (from both JP/intl fans) about people's views being constantly blocked, getting hurt or pushed around, the oshi-jumpers hurting themselves, or breaking venue property. It's all second-hand and obviously not from a very large pool, but it seems like the minority ruined it for the majority. Maybe they'll ease up on it after a while.