Lexus Dealer Responsibilities related question

[NetLexus]

I have a Lexus LS460L Executive model, been having some start-up hesitation last two days. This morning it wont start, the AAA battery service guy came and quickly found out that one of the battery terminal had a overwhelming acid corrosion so much that the terminal itself has been eaten away. Question: is it not mandatory or a norm for the Dealership to check the battery and terminal during each oil service? I always get the oil service done at the dealership and even got the new battery with them exactly three years ago.... so I am wondering if the dealership missed their responsibility? It seems like they never looked at it in three years resulting in terminal being completely eaten away.  Any pointer may help.  

[GOLD NUGGET]

You can look at your service receipts to see if they checked that the battery was checked and when.  

If you want to make sure it doesn't happen again you can buy a can of NCP-2 battery corrosion preventive, and brush it on the post.  Look on Google to locate some, it's about $12  for 4oz  that much would last years. Of course the battery on the LS is not easy to uncover.

[Boatpix]

If you get a 10mm battery ratchet for $15 on Amazon it makes it a snap to remove cables from terminals.  I know this from last week when wifey closed trunk on luggage strap and this forum suggested 30 second disconnect of battery will reset trunk lock that was jammed at Houston airport.  A month ago I had battery failure in put-in-bay Ohio and had independent replace battery and he said I had similar corrosion as to what is described by poster. No Lexus dealer nearby so used independent or intuition.