I haven't found this to be the case. Let's take a trivial impetus idea I came up with, to use the next time I move: I can put a piece of candy in each box (on the bottom). If I just grab a handful of Creme Savers, put them in my pocket, and drop one into each box as I pack, that's easy. I don't think I'd experience any akrasia about doing that that wouldn't also stop me from packing, so assuming I get my packing done, the candy will also be packed. Then, when it comes time to unpack, the fact that every box unpacked means a piece of candy would serve as a trivial impetus to get unpacking accomplished.
Ah - you're setting up the impetus intertemporally, not "right now for right now" as I'd assumed. Good catch, this might work.
There is a flipside to the trivial inconvenience: the trivial impetus. This is the objectively inconsequential factor that gets you off your rear and doing something you probably would have left undone. It doesn't have to be a major, crippling akrasia issue. I'm not talking so much about finishing your dissertation or remodeling your house, although a trivial impetus could probably get you to make some progress on either. I'm talking about little things that make your life a little better, like trying a new food or permitting a friend to drag you along to a gathering of people and pizza.
An illustrative anecdote: the first time I tried guacamole, I was out with my family at a restaurant and my parents decided to order some. The waiter came out with a little cart with decorative little bowls full of ingredients and a couple of avocados, and proceeded to make guacamole right there with all the finesse of one of those chefs at a hibachi restaurant. He then presented us with the dish of guacamole and a basket of chips.
If my prior reasons for avoiding guacamole had been related to concerns about its freshness or possible arsenic content, this would have been a non-trivial reason to try the new food, but they weren't - I was just twelve, and it was green goop. But on that day, it was green goop that someone had made right in front of me like performance art! I simply had to have some! It was delicious. I have enjoyed guacamole ever since. I would almost certainly have taken years longer to try it, if ever I did, had it not been for that restaurant's habit of making each batch of guacamole fresh in front of the customer.
Not all trivial impetuses have to be so random and fortuitous. Just as you can arrange trivial inconveniences to stand between you and things you should not be doing, you can often arrange trivial impetuses to push you towards things you should be doing. For instance, I often get my friends to instruct me to do things when I'm having trouble getting moving: sometimes all it takes to get me to stop dithering and start making the pasta salad I agreed to bring to a party is someone agreeing when I say, "I should make pasta salad now". Or "I should go to bed now", or "I should probably pay that bill now".
Does anyone have any other ideas for trivial impetuses that could be helpful in fighting small-scale akrasia (or large-scale)?