Unfortunately, there are some worse places that kids put their hands than shopping trolleys at times.  I have an 18 month old that used to be totally pre occupied with getting into the bathroom when I turned my back and with plonking matchbox cars or leggo into the loo and then fishing them out!  Ewwww...

Then digging in dirt outside.   They have all done it so far...  shopping trolley would be the least of my worries.  In fact I have never even given it a thought. 

Kids in daycare center’s share left right and center before you can even do anything about.  They use toys, loos and everything every other child does.  Eventually you just have to stop worrying and just cope with whatever turns up as it turns up.