Yeah, I guess a big one in an enclosed space could be pretty loud.
I just like to mention it as a warning... that rattlesnakes aren't necessarily all that loud. If somebody is expecting the noise they hear on a Western, they could overlook smaller snakes which are just as dangerous. A small rattler in tall grass sounds almost like a bug if you aren't familiar with it.
I've been around rattlesnakes enough that they're really not that big a deal. But if you're in an area where you know they're around, it's best to make noise and knock around with a big stick or something. They'll let you know if they're there
A lot of people keep a gun handy to kill them. A shotgun works... though that's like killing a wasp with a sledgehammer. IMO a .22 or a .38 with rat shot is a better option. But I don't carry a gun around most of the time... a big stick or a steel fence post works fine.