Yes, a request. For the reason that the serving person is by nature an autonomous organism who has sole control over his/her behavioural response to the customer's act. By implication of that, the customer's order has the function of a request for the serving person's a) attentiveness and b) obedient action so as to provide the customer with the requested item. Hence the conventionally used verb "to order", which literally means exerting the power to cause the recipient to respond involuntarily, is strictly inappropriate.
Society generally educates children to be aware of the autonomy of persons they seek assistance from; I do not know of any cultures that omit words/ expressions equivalent to "please" for indicating that they are uttering a request.
Based on recent EMCA work, it might be better thought of as a type of recruitment. But that depends on if you're thinking in terms of EMCA or other frameworks for looking at pragmatics.