Depends. Gut feeling is subtly grass if it’s an independent shop, but FUCK THE TORIES if it’s a chain, but then people in, say, Tesco are on low incomes and get bonusses based on a variety of things including stock shrinkage, so idk.
Gut feeling is still to err on the side of caution and not get involved, but the last time i did that a guy who’d nicked four massive tubs of baby food basically threatened and assaulted somebody, so it’s a toughie.
I reckon i probably base it on what reduces my chances of getting knocked out more than what my moral view is on shoplifting.