How do we stop "using Duck/t tape" being given as an answer to most quesions? It does not seem a useful answer to me, as it is hardly every the best way of fixing something.
For any post, if you do not like the content, don't vote for it (or vote it down). Comment if you feel a solution is being applied inappropriately.
But it's not really the job of this community (through meta) to place a moratorium on using one product (or not) in their answers. Surely, duct tape has some legitimate use. Even if we agreed that duct-tape solutions are being applied disproportionately, how would we determine what the proper quota is for "use duct tape" answers? That's what voting is for.
Duct tape, ironically, is not the best product for sealing ducts. There is foil tape which feels like thick tin foil which adheres better and longer.
Duct tape is a great short term fix. Your hose (home or car) springs a leak, the tape will get you through a short while until a repair can be effected. Not a permanent solution. (as already stated, non-appropriate duct tape answers should be down voted.)
If it is given in jest then it should be voted down and possibly flagged.
If it is given with no context -- how exactly would this work -- then a comment should be left asking the user to explain.
If it is given with context and an explanation, then it's probably OK as long as it's not dangerously bad advice.