The Draken have enough radar to fly a trail, as have most fighters used as interceptors in the western world anyway, and visual identification can be done if the interceptor approach with modest rate of closure 1-2000ft below the target.
(If no radar available, one would think GCI vectors are available for the fighters)
If the weather is so bad that they are still unable to do a visual check, they should stay the f*** away, because as some here has stated, joining on a aircraft in thick IMC is DANGEROUS BIG TIME!
BTW: I cannot se one sigle reason why some air forces intercept airliners without even trying to reach the "offender" on guard or othervise.
Anyone wanna bet how long it's gonna be, before we get a midair from all this?