I've got two saves now where for some reason, after leaving the strip and fast travelling to Freeside or New Vegas Medical Clinic, I am locked out of The Strip at both entrances.

Tried waiting until morning, but now The Strip is requiring a key to enter, stopping me from doing anything on The Strip.

Just got the +1 luck nightwear and a luck implant, and now they are useless to me .

I know that the securitron gatekeepers have keys on them. You could maybe kill one of them silently? I'd try the Anti-Materiel rifle from a distance. Failing that, you could try to get in via the NCR monorail at Camp McCarran.

I think you need to finish the mission at the NCR McCarran Base to investigate the break-in in the control tower. After that portion of the mission, I could get back into the strip.

There's no way to get back in without killing all the Securitron gatekeepers and gaining infamy.

Doing the Camp McCarran mission is not a suitable solution for The Strip being locked.

I already passed a Science 80 check to reprogram the gatekeepers to let me in.

Hence it's a rather annoying bug that should be fixed.

This is completley false, been here done that. You need a sniper rifle go up to the gate choose the upper right most securitron and back up while making sure he dosent disapear off the screen. I took my shot from the blue car freeside gate 1shot 1 kill bullet through the monitor, gun health at 51 damage. Remember to kneel so you get the critical damage. Knock him off his @$$ take the key and now you'll never have an issue again cause i'll always have a key

Did you get

Well I thought a Science skill of 80 was pretty high just to get through a gate, so why isn't it permanent?.

Just thought it was a round about way of doing something so simple.

Got locked out myself, used Euclid's C-Finder to kill the gatekeepers without being seen, looted a key, problem solved!

kill the securitron gatekeepers using a sniper rifle with silencer modded onto it. as long as you are not detected, you will not gain infamy. i believe 'gunrunners' is the best place to find the sniper rifle silencer. i realize that that does not change the fact that you should not be locked out of the strip AT ALL, but the silencer has helped me get around many bugs that would normally have put me on horrible terms with many of the factions. good luck.

just take the monorail, you have to wait till the guards change shift (8:30AM I think) or else they will attack you (unless your idolized)

also, I found it safe to never fast travel from the strip., go back out the gate first, I have gone back out several times and it has said it was locked, but you can open it from the inside, which seems to unlock it again.

I ended up getting a key, I had the NCR ranger you can summon, and for whatever reason, she won't go through the gate and goes hostile on the gate securitrons, so I let her kill them, it doesn't mess with my rep, and I loot the key from the dead guard.