Well, as much as governments love rules I guess they accept that it's unreasonable to expect people to get out their measuring wheel to check, or to be denied a nice walk because going around the one-way system makes it 5.2 miles!
It's not so bad for Edinburgh, which has pretty much the whole city fudgably within 5-ish miles. Otherwise really small numbers for a lot of places. Interesting that Blair Drummond and Highland seem to be opening up regardless though. Presumably they're banking on the 5-mile guidance being shelved fairly soon after reopening (similar guidance in Wales is planned to be lifted in the first week of July), so in fact it would create basically a soft opening for them.