> It seems the only way to protect against theft is to ride an old bicycle.

I like this blog on that topic:

https://calpaterson.com/bicycle-threat-model.html

> One father I know had his primary-school-age daughter "decorate" his commuting bicycle with girly stickers and pink glitter. If anyone examines his bicycle closely he looks like a complete loon but I think his motivation is right: it's going to be much less appealing to steal when it's covered in Miffy stickers.