Recently, I've noticed a slight salty taste in a few beers. It's generally toward the end of the glass, and it's generally when I'm dehydrated. It's happened with Long Trail Ale and Stone Arrogant Bastard, both in the past two weeks.
So, I guess this is a multiple choice question:
A) The beer actually has salty flavoring, and I don't taste it until the beer is a bit warmer.
B) My friends are dicks and threw salt in my beer when I went to the bathroom.
C) I'm super dehydrated.
Well, there are salt ions in all beers. It is possible that as your palatte fatigues you are just more sensitive to it.
There are, however, other flavors in beer that could be interpreted as salty, but are something else. Particularly the hop profiles of the beers, perhaps.
The good news is that you need more experimentation.
Today: Drink 4 glasses of water during the day, then drink 4 long trails at night and see if they seem salty.
Tomorrow: Don't drink the water, wear four sweaters and walk around the house a lot. Then drink the 4 long trails at night and report back.