Re: the potential risk posed by the traveler will be recalculated
.I am sure there are UK companies who will sell you an armoured personnel carrier.
Last time I heard, UK military goods are not very welcome in Republica Srpska (that is the detour I had in mind). So I would rather stick to a second hand BTR-2.
On a more serious note, the list of countries looks weird. I have not crossed a Baltic state border lately, but the other "testers" have issues which have nothing to do with "lie detector needed" on their border checkpoints. It is the last place I would test something like this.