I've never done one. And to be honest I doubt I ever will (never say never tho'). Riding solo I'm happy to just record my rides privately on rwgps.I think your 'check the route to see if there's a shorter way' advice is spot on and allows a DIY route designer to minimise the 'extra distance in case' approach. I'd just not introduce the 'cheating' concept, because noone's cheating anyone.
How did your last DIY go, btw?
TBH the OP never mentioned DIYs . As I read the OP it was a query about how to set up a ride that was like a (calendar) audax, and had similar spacing of checkpoints. No intention of submitting it for validation. So my reply was how to replicate the control spacing I've seen on calendar events. Maybe I mis-read it.
My suggestion "try cheating" was a suggestion of how to test the proposed controls so it was similar to what you might encounter on actual (validated) audaxes. Works just as well without the "c" word. Maybe "Try finding shortcuts" instead if you prefer that.