Lelit boiler is 300mL and will be primed no doubt, so *technically* it wouldnt be allowed purely on fluid levels ( source: http://travelsecure.infrastructure.gov.au/international/lags/index.aspx ). If you empty it, they could argue its a partially filled liquid container.
The reality is if you check your luggage, and then try and take it through screening and they decline it, what then?
Hotel wouldnt care at all.
In reality, I think theyd let it through though.