Kids eh! We have a rule, reinforced by good old fashioned fear and threats. All three best bikes live leant against the wall in stacked formation, with a ground anchor in the garage floor, and a 4m cable securing all three, wound through the frames and wheels and ending with a d-shackle through whichever bike is outermost (usually mine). The kids are told in simple terms that if they don't stack and lock their bikes in this way, the burglars will come and steal them
, and as it was their money that paid for the bikes in the first place, it will be their money that replaces them. This has worked unfailingly, and both have been given the responsibility of making sure the bikes are stacked and locked each night.
They have also been shown how to stack them carefully, and taught how to avoid scratching or damaging any of them. This too has worked. They are perfectly aware that if they scratch mine they will be beaten mercilessly.......
To the OP; I store six bikes at work. They all have individual floor-mounted axle stands which have a fork slotting between the dropout and the brake disc. They are small and neat, are not dependant on tyre width ( I couldn't fit 2.25" Tyres into a rack) and cost about £20 each.