Speaking of Finland, my father was there for two years as a young man, and came away writing all his 7's with a - through them. This is the way I grew up writing my 7's.
A few years back, someone looked at a 7 I had written and said something about it being pretentious to write that way. Made me pause for all of about 2 seconds before deciding that *my* way was better. Who wants to have a bunch of naked 7's running around?

Ti'So what if I'm pretentious...I'm still right!'cia