careful about running

[navi tasan]

1) You must be careful about shoplifting. You might get caught.
2) You must be careful about shoplifting. People might try to steal things from you when you are not looking.

3) You must be careful about stealing cigarettes. You might get caught.
4) You must be careful about stealing cigarettes. People might try to steal cigarettes from your store when you are not looking.

5) You must be careful about running. You might hurt your knee.
6) You must be careful with running. You might hurt your knee.

Which are correct and meaningful?

 

[emsr2d2]

In every sentence, I'd change "about" (and "with" in #6) to "when".

 

[Tarheel]

You must be careful when shoplifting. You might get caught.

There's always that risk, isn't there?

As for, "You must be careful when shoplifting because people might steal from you," that's irony, isn't it?

 

[navi tasan]

Thank you both very much,

'When' will work when 'you' are doing the stealing, but #2 and #4 you are the potential victim. You have to be careful that stealing doesn't take place.

 

[Tarheel]

You have to watch out for shoplifters.

**in #2 ....

 

[emsr2d2]

2) You must be careful about shoplifting. People might try to steal things from you when you are not looking.

If this is addressed to a shopkeeper/shop owner, the first half doesn't work. Use Tarheel's suggestion or something similar, such as "You have to be alert to shoplifting/shoplifters" or "Keep an eye out for shoplifters". The second half is unnecessary. The idea of someone stealing something from your shop while you can't see them is contained entirely in "shoplifter/shoplifting".