Mizter T wrote:

But since I figured out that keeping my Oyster card in my back pocket
was a bad idea and stopped doing so I've had no problems at all. So
that's my basic bit of advice - by all means get and use an Oyster
card, just don't sit on it.

For what it's worth, I've had mine in my back pocket (and there's been
an awful lot of sitting on floors, sitting down, etc), since I first got
it in 2003.