It seems more like visiting an old relative serving a life-sentence with no parole.
Yep thats about the size of it.

It need not be expensive though. If the site is close enough your joining can include your regular target shooting and range use with your section 1s, range fees you would pay wherever you shoot. The pistols dont have to be pristine perfect examples, you probably wouldnt want to shoot it if it were. The storage rental is the worst extra cost, the sites have an increased insurance and security outlay to recover.

The lock in is not a solo thing, heritage sessions tend to be maybe once a month so quite a few attend together for a chat and a shoot. You cant keep ammo for your 7.3 at home so theres a fair bit of reloading done on site. And a lot more chatting and discussion than a regular shooting session.