It is best to water new seedlings from the bottom. That said, of course seedlings started in the garden will be watered (or rained on) overhead. Many of them will fall over for a short time and then right themselves. If they are already leggy, they might stay on the ground, turn, and sent just the top of the plant upright.
Out in the garden seedlings can be bent over in heavy rains, but growing in the outside also seems to strengthen the stems so they withstand tipping over a bit more. That is another reason we "harden" them off before direct planting in the ground. It isn't just to prevent sunburn, but to build sturdy stems by exposing them to the breezes (or wind) in the yard.
I wouldn't worry overmuch about week old seedlings. They should straighten up just fine. Check for a finer spray on the water can or water from below.