Wylie, I suspect you are talking about little quarter-turn taps that you put to stop the water as soon as it comes through the wall? They are a godsend to have. We put them in whenever we do any major under-bench type plumbing repairs, or replacing kitchen/bathroom jobs. Also behind toilets- you can then change cistern washers etc without turning mains off. I didn't realise they'd become a requirement.
Use the ones with ceramic internals and they should be relatively maintenance-free (although nothing really is!). Tenant can quickly and easily turn them off in a situation like the OP's, or if they notice a slower leak into the cupboard, etc. One saved our brand new reno-ed kitchen in abt 2010, so well worth the effort IMO.
Edit: glad to hear it all worked out satisfactorily, kennyboi.