Suppose it depends on my image at the table. I could see lead-betting this flop if I had a tight image and had some fold equity involved. If the SB leads, probably fold. If I check, the guy behind me bets, everyone calls and I end the action, I may call.

If I'm getting run over, can't semi-bluff here - I'll get called by everyone or raised. More than three players in makes it harder, less likely for me to lead bet. If the Q was an A, I probably wouldn't lead either.

Second example, less likely to bet out. Lots of people stay in with second pair. Check and fold seems better.

ScottieK