All smashers can spear with the pointed dactyl and given that the tip is barbed, they can cause quite a bit of bleeding. I think the smallest gonodactylid I've had draw blood was about 15 mm. Personally, I don't worry about them until they are around 35 mm. Different species hare harder to handle than other. A few of my least favorite species to id because they stab rather than smash are G. smithii, N. curacaoensis and N. austrinus.
During the 80's, I maintained a lab in Panama monitoring Neogonodactylus populations. We collected and identified close to 500 stomatopods a week for 8 years. I sent graduate students and undergrads down to Panama to conduct the sampling. All data were entered into waterproof notebooks. I now have about 30 of them on my self. When people ask me about being injured by stomatopods, I get up and randomly take one of the data books down and quickly leaf through the pages. Every so often, I will come across a series of pages with brown stains - the blood of newly arrived students doing their first few weeks of ID-ing.
Roy