Ferry company Hoverspeed has started using a new tactic in its feud with Customs and Excise.
The firm announced in August that it was planning to sue Customs for £30m.
It claimed customs officers were being over zealous and were putting people off travelling across the Channel.
Now Hoverspeed has started issuing notices to all its passengers giving advice and asking people to fill in questionnaires about Customs.
Among the tips is that people should demand to know a customs officer's name and badge number if they are stopped.
The leaflet also asks whether people feel threatened by customs officers, and if they were told by officers not to travel with Hoverspeed again.
Graham Hooker, from HM Customs and Excise, said: "I think Hoverspeed think we are unfairly targeting them as a company - now that is not true.
"What we are actually doing is tackling the smuggling threat and there is a particular threat on the route that they use.
"It is a very fast route, it is a very short route and it is very attractive to people who are racketing to bring in revenue goods which aren't for their own use."
Hoverspeed claims the campaign against alcohol and tobacco smuggling through the Kent port has targeted too many people on innocent shopping trips.
But Customs and Excise has said that it would vigorously fight any case brought against them by Hoverspeed.