Repeat need for bilge pumps while away from boat is a worry for sure...
However, I believe that worry should be mitigated against worry for other calamities that may happen due to incessantly charging batteries. Such as fire due to charger failure/short - Battery over heating and/or melting/exploding - Improper wire gauge that heats too much and has its casing melt creating a hazard - fire from shore power hookup... I do not know the stats regarding what % of sinking occurs from unattended leaking raw water as compared to fire from electrical items on a boat; batteries and chargers and shore lines specifically. I'd imagine that unattended leaking is more often the cause. But don't forget... just because a boat sinks at dock does not mean it was a "leak" of raw water per say... heavy rain is also a culprit.
Anyway - I believe that by Keeping my boat
hulls and thru hulls in good condition as well as that not keeping my boat electrically hooked to shore power and therefore having no battery charger running while I'm away give me best chance for continued battery life and floating boat having no complications.
Don't forget - Insurance company pays for replenishment or replacement of sunken boats... but not for replacement of ruined batteries or fried chargers... that I know of!
All in all... boats are a some what of a worry regarding always keeping them floating. It is my feeling that as long as I keep all thru-hulls well sealed and in good condition and make sure other potential raw-water intrusion locations are in a leak proof state that my boat will sit fine on its bottom in the water without need for charging batteries.
Happy Boat-Float Daze! - Art