The vent cover fastener on the Seneca's IS a "snap type" cover, that does REQUIRE some "umph" to get them to open (along with a ladder to reach them!!). You will NOT break them. These are NOT the "twist" type fasteners that older rigs have that do need tightening. You can LEAVE THEM OPEN when traveling; however, make sure you close them if you store your rig for a while (you do NOT want spiders, etc... making a home in there!). They are hinged at the top and with the rain cover, they don't "flap in the wind" as you're driving.
Highlands Ranch, CO
2015 Seneca 37TS ("Screaming Eagle")
2009 Hummer H3 ("Ranger")
2005 Chevy 2500HD ("Max")
2008 MasterCraft X-15 ("One More Time")