Many problems besides wep
Some people realize that WEP is inherently insecure these days.
However even if WEP were secure there are many other security issues with WIFI hotspots. These apply even to the more secure WPA.
1. You have to trust the operator of the hotspot to not be snooping traffic or stealing your data (as well as their ISP). And that they haven't been hacked.
2. You're can't be positive that you've actually connected to the hotspot you intended to, it could be a hacker's access point falsely advertising the same ESSID, you or your laptop software might decide to connect to it initially because of a stronger signal.
3. Attacks that affect traditional wired networks still apply to wireless despite WEP/WPA which only aim to secure the link to the AP. For instance ARP attacks, etc. Although with the right hardware it should be possible to separate clients from each other.
The solution is, if possible, to use a VPN for all your sensitive traffic. This way data would be safe even when going over public channels.