You can shake any tomato flowers you want. You might get more tomatoes. You might not. Tomatoes are pretty smart about getting pollinated. If your tomatoes are inside a greenhouse, where there is no breeze to shake them, manual shaking might be useful. In fact, commercial indoor growers do precisely that, unless they have a lot of fans.

I don't know that it has ever been "recommended" to hand pollinate them and sincerely doubt that many do it. Assuming outside growth rather than in GH they produce abundantly all on their own. But it takes little effort to rattle cages now and then so if you want to spend the time and energy it sure won't hurt anything.

Dave

If you're not getting much production, it could be the soil, rather than the pollination. Getting a soil test might be a good idea.

I know in my garden, though, historically, some cherry varieties hardly produce (e.g. Gardener's Delight) and some are prolific (e.g. Sweet Orange Cherry). Changing the variety may help.

Which cherries are you growing? Are you having issues, or just wanting to know?

I just wanted to know.

Since they are self pollinating a slight breeze will do the work for you. You shouldn't need to intervene at all.