I’ve used trained porpoises instead of dolphins and nobody understood anything and it was a disaster. I think you should only use one if you try.
There was a Daily Show field report 10-15 years ago that I can’t find. Probably before gay marriage became legal across the country. Anyhoo, the jist was two actors went to diners in the midwest or the south with one taking a knee and making a marriage proposal. Random patrons then applauded and/or congratulated the “happy couple.”