"We just came back from a fun and productive trip to Florida
where it was legal
to lobster and spearfish."
Not quite. It is legal to do both, if and only if you have a license
and it is in season and you follow size and bag limits for each species. On lionfish you get a pass, but that's probably the only species most states follow that policy with.
FWC have a reputation for vigorous enforcement, but some years ago one NYS DEC officer set a new standard for lobster licensing. He confiscated "all equipment
involved in the infraction" and reputedly left one diver standing in the parking lot in his underwear, holding his citation.
When in doubt...try to find the actual regulations
on a national web site for each jurisdiction. Many are rather protective of native fishing rights.
A friend of mine got around the regulations
prohibiting "landing" of various shellfish one year by just having scallop sushi while he was still in the water
. Perfectly legal that way. He'd read the rules.