at least in my 40 gal with my girls it is....i have one on the right hand side and every day i'm putting it back up cause it continually falls down....luckily its not that high. Two of the three suction cups just suck. So i'm thinking that the next time i clean out the tank completely and remove the girls i'll silicone three suction cups with hooks onto the glass, leave it for 48-72 hours and then just hook the hammock in place.
I'm doing this for my new crested tank today actually. Siliconing suction cups with hooks to the glass to help hold some of those vines in place. I'll be doing the same for the hammock most likely LOL. I can't wait to have them home, the tank looks awesome already, and i'll be getting another of similar size for Zeek and doing the same setup.
Something else i noticed lately is that when Dot and Abby had the reptile carpet over their UTH they loved laying on it so when i put the third UTH in the 40 gal i put the carpet back on it and most of the girls are laying there. I don't know if they prefer the feel over the tile, but it seems that way. So while i was out the other day i picked up some of those hot pads for your table for hot pots. I'm going to put it in the other warm spots. Hopefully the girls will spread out a little more. I've also made the coconut and cave hides, humid ones. I just cut some containers down to size and put them underneith. This was done cause even with 3 humid hides, 3 girls who are in shed are all chosing the cave and coconut hides and haven't completely shed. Now they don't have much of a choice if they wish to be inside a hide. hehehe
Sorry for rambling LOL
Red 
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Crested Gecko Zeek:1.0
LEOS: Boo: 1.0 normal , Bronx & Nala: 1.1 blizzard,
Lily: 0.1 patternless, Abby: 0.1 albino, Zoe: 0.1 reduced pattern, Dot: 0.1 hypo
Chip: 1.0 papillion (small dog)