I'm one of the guys that always unplugs unattended boats if I see 'em plugged in over winter. I'd prefer not have someone else's cooked batteries and/or failed charger ruin my upcoming summer...
Normally I'm doing it ahead of time because, say I'm heading down tomorrow afternoon, I want to be sure they are charged and I can get the hatch open.
Why is someone else's dead batteries ruining your summer? Unless I'm not understanding what you're saying ...