Dripleaf should make you fall off in front of it.

When the dripleaf tips you off you fall onto the block directly under it. However dripleaf can only be placed on non dangerous blocks. It can't be on lava, fire, above air, or atop a pressure plate. This means that falling off is completely safe. However if you fell off onto the block in front of the dripleaf this could be used for falls, lava, and all sorts of traps. Currently the only penalty to falling off is getting back on. If you only had a few seconds to get off the block or fall into danger it would be more fun for gameplay.