True dat. I've come to hate "you start in prison" scenarios for exactly this reason. Many classes expect access to certain items; fighters have their favored weapon types and armor, wizards need their spellbooks, clerics need holy symbols, et cetera. When you build a character, you do so in the expectation that you'll be able to pick suitable starting gear. Then you find out your gear is all gone and half your abilities are useless till you get it back... if you get it back. Sometimes you have to go through several sessions with scavenged crap.
It's not as bad if you know it's coming and can plan for it. Even so, adventure designers need to be extra careful to provide for PCs' needs. Spellbooks in particular are an issue. A wizard's spellbook is a major part of the character and losing it is a big deal. 5E wizards can get by okay without it for a while, but permanent spellbook loss is a crippling blow even in 5E; inflicting such a loss with no way to avoid it is grossly unfair. If you take a wizard's spellbook as part of the setup to an adventure, you need to give the wizard a way to get it back.