My guess is that most WordPress theme users do not know what the lock-in effect is. That is, until they try to switch themes one or two years later. It’s something theme user need to know about so they can choose the right theme today. Many have targeted their writing about the lock-in effect at theme developers, urging them not to register post types or shortcodes in themes. Few have written to the user, though. Here’s my attempt on the churchthemes.com blog.