Well I've never come across any threads with wheels coming off.
As far as I know if they're good quality, with proper, longer bolts then they're safe. If you buy some cheap **** they could crush from what I've read. Other than that I know wheel bearings can wear a bit faster but what is a bit? 10yrs?5yrs? Dont know but thats not something you replace often. Car looks much better thats what I was guided by, but be careful as I've put 13mm in the front and I think any wider could cause some rubbing, unless thats just coz car is slightly lowered.