Not often, but I did a few times when they were no trollies and I had my own trolley bag for a bigger shop. I felt a bit uncomfortable, but I did it as conspicuously as possible, so it is obvious that this is just me shopping and not stealing. I wouldn't do it as a habit though and certainly wouldn't put it in my handbag with my other stuff, that feels dodgy and maybe a bit rude? Like you feel entitled to everything and payment is just an afterthought. Also don't do the "eat in shop, pay at the till" thing, it's also rude in my view, if it's the norm, rather than an exception (eg. an overwhelmed parent going along with a child grabbing something).

Both are divations and transgressions of the rules and codes that operate in the shops, but neither is illegal. It's ok to do it if you must, but not really ok to do it as a habit, because if everyone does it, the shop order goes to sh*t, staff will struggle to know who is stealing and who is not, and generally you are showing yourself as a person who thinks rules don't apply to them and you are special because you are entitled to flex the rules and nobody will notice/ care. Well each such activity adds extra load to the staff's load -because they now have to look at all these handbag people to make sure they pay.