If enough people do what you're considering doing yourself, and for similar reasons ... then you could be ensuring a GENERATION, if not longer, of continuous Democrat victories. I'd have thought that this was the most undesirable, least acceptable, outcome imaginable ?
... and I wouldn't write off any one minor Party, not even the Libertarians. If any get ENOUGH support, they could enjoy rollercoaster success over successive elections.
Here, we now have UKIP ... a creditable Party, wanting us out of Europe, firm control on immigration .. laudable policies. A decade ago, they were in the political wilderness, existing, but nobody took them seriously. Today they are still a 'minority' Party, but now a serious threat to the major ones, nonetheless. They could cost our Conservatives the upcoming election through taking too many votes away from them. Result .. LABOUR gets in, probably propped up by the SNP ... and neither of those Parties, if they win, will allow the British people any Referendum on continued membership of the EU. We'll all just be stuck with it.
Perhaps this'll appeal to minority voting-wannabes ? It's a Party Political broadcast by one Al Murray ... standing for election in South Thanet, in Kent. He IS actually standing for election, though it's also a purely joke candidacy. Al Murray, AKA 'The Pub Landlord', is a comedy creation.
Here's his election video --- enjoy ! ---