Just a quick follow-up to say that unfortunately, this tweak didn’t please everyone, so we have now implemented an option to let you choose which Activity type you would like to be your account’s default. You can also choose for your default to be blank (and therefore force you to choose one each time).
You can configure this option in Settings → Customer settings. Thanks.
Yes, there is a good reason (very much due to a technicality behind the scenes), but we can always look to re-work it so you have more flexibility here. If you’d like to open a feature request for this, we’ll see what we can do