no. you can't do that. you're not supposed to trust me with tbt, that's not how the world works and not how my way works
the 5tbt is the initial payment, but you do not need to pay any additional tbt costs until you're ready to receive your villager.
but if you decide to cancel after more than an hour has passed, i keep your 5tbt as a compensation
(and on a informative note, the 5tbt can be refunded if the first hour of reserving has not passed yet->so you're still able to get a refund for your 5tbt if you don't want grizzly within the next 43 minutes ish?)