I have a scenario where once Account.createUser is called, no other Meteor.apply or Collection.insert, et al. go through to the server.
So, here, the last call will not go to the server:
Accounts.createUser(username: "tmp_username", password: "tmp_password")
Lists.insert(name: "Untitled", datecreated: new Date())
However, removing Account.createUser, all calls make it to the server.
An important note: It seems that the calls are queued on the client because I make the above calls with Accounts.createUser, I don't see the results of List.insert. However, if I go to my source, save (with no edits), this causes Meteor to reload something which then opens the flood gates for these calls that were queued before.