Mad... Interesting. Unfortunately your profile reveals nothing. Where do you work? Are you an ATCO at a licenced ATC Unit at a major airport.
I used conditional clearances all my life at two major airports and one training airfield and never had any problem at all. I was properly trained to employ the technique and trained many ATCOs to do the same. It's a very valuable tool in achieving the movement rates demanded by the airlines and the airport authority.
I hope you don't fall into the same category as a trainee we once had at Heathrow - wouldn't ever use 3nm spacing because it was considered to be "too dangerous"!!! Needless to say a posting out resulted.
It's possible to shift a heck of a lot of traffic, aircraft and vehicles, in perfect SAFETY using conditional clearances. You just have to know what you are doing and do it well.